diff --git a/doc/sql.extensions/README.identity_columns.txt b/doc/sql.extensions/README.identity_columns.txt
index 5e97b5d405..5c5970ef8c 100644
--- a/doc/sql.extensions/README.identity_columns.txt
+++ b/doc/sql.extensions/README.identity_columns.txt
@@ -18,10 +18,13 @@ Syntax:
         INCREMENT [ BY ] <value>
 
     <alter column definition> ::=
-        <name> RESTART [ WITH <value> ] |
-        <name> SET INCREMENT [ BY ] <value> |
+        <name> <alter identity column option>... |
         <name> DROP IDENTITY
 
+    <alter identity column option> ::=
+        RESTART [ WITH <value> ] |
+        SET INCREMENT [ BY ] <value>
+
 Syntax rules:
     - The type of an identity column must be an exact number type with zero scale. That includes:
     smallint, integer, bigint, numeric(x, 0) and decimal(x, 0).
diff --git a/src/dsql/DdlNodes.epp b/src/dsql/DdlNodes.epp
index 83740b621b..a701117574 100644
--- a/src/dsql/DdlNodes.epp
+++ b/src/dsql/DdlNodes.epp
@@ -6214,7 +6214,7 @@ void RelationNode::defineField(thread_db* tdbb, DsqlCompilerScratch* dsqlScratch
 		ObjectsArray<CreateDropConstraint> constraints;
 		bool notNullFlag = false;
 
-		if (clause->identity)
+		if (clause->identityOptions)
 			notNullFlag = true;	// identity columns are implicitly not null
 
 		for (ObjectsArray<AddConstraintClause>::iterator ptr = clause->constraints.begin();
@@ -6277,9 +6277,9 @@ void RelationNode::defineField(thread_db* tdbb, DsqlCompilerScratch* dsqlScratch
 		if (clause->collate.hasData())
 			DDL_resolve_intl_type(dsqlScratch, field, clause->collate);
 
-		if (clause->identity)
+		if (clause->identityOptions)
 		{
-			if (clause->identity->increment.orElse(1) == 0)
+			if (clause->identityOptions->increment.orElse(1) == 0)
 			{
 				status_exception::raise(Arg::Gds(isc_dyn_cant_use_zero_inc_ident) <<
 					Arg::Str(field->fld_name) <<
@@ -6299,8 +6299,8 @@ void RelationNode::defineField(thread_db* tdbb, DsqlCompilerScratch* dsqlScratch
 
 			CreateAlterSequenceNode::store(tdbb, transaction, fieldDefinition.identitySequence,
 				fb_sysflag_identity_generator,
-				clause->identity->start.orElse(0),
-				clause->identity->increment.orElse(1));
+				clause->identityOptions->startValue.orElse(0),
+				clause->identityOptions->increment.orElse(1));
 		}
 
 		BlrDebugWriter::BlrData defaultValue;
@@ -7862,7 +7862,7 @@ void AlterRelationNode::modifyField(thread_db* tdbb, DsqlCompilerScratch* dsqlSc
 					RFR.RDB$IDENTITY_TYPE.NULL = TRUE;
 				END_MODIFY
 			}
-			else if (clause->identityRestart || clause->identityIncrement.specified)
+			else if (clause->identityOptions)
 			{
 				bool found = false;
 				AutoRequest request2;
@@ -7874,27 +7874,26 @@ void AlterRelationNode::modifyField(thread_db* tdbb, DsqlCompilerScratch* dsqlSc
 					const SLONG id = GEN.RDB$GENERATOR_ID;
 					const MetaName genName(RFR.RDB$GENERATOR_NAME);
 
-					if (clause->identityRestart)
+					if (clause->identityOptions->restart)
 					{
-						const SINT64 val = clause->identityRestartValue.specified ?
-							clause->identityRestartValue.value :
-							(!GEN.RDB$INITIAL_VALUE.NULL ? GEN.RDB$INITIAL_VALUE : 0);
+						const SINT64 val = clause->identityOptions->startValue
+							.orElse(!GEN.RDB$INITIAL_VALUE.NULL ? GEN.RDB$INITIAL_VALUE : 0);
 
 						transaction->getGenIdCache()->put(id, val);
 					}
-					else if (clause->identityIncrement.specified)
+
+					if (clause->identityOptions->increment.specified)
 					{
-						if (clause->identityIncrement.value == 0)
+						if (clause->identityOptions->increment.value == 0)
 						{
 							status_exception::raise(Arg::Gds(isc_dyn_cant_use_zero_inc_ident) <<
 								Arg::Str(field->fld_name) <<
 								Arg::Str(name));
 						}
 
-						MET_update_generator_increment(tdbb, id, clause->identityIncrement.value);
+						MET_update_generator_increment(tdbb, id,
+							clause->identityOptions->increment.value);
 					}
-					else
-						fb_assert(false);
 
 					dsc desc;
 					desc.makeText((USHORT) genName.length(), ttype_metadata,
diff --git a/src/dsql/DdlNodes.h b/src/dsql/DdlNodes.h
index 2604a6765f..a46b7b6db7 100644
--- a/src/dsql/DdlNodes.h
+++ b/src/dsql/DdlNodes.h
@@ -1307,11 +1307,13 @@ public:
 	struct IdentityOptions
 	{
 		IdentityOptions(MemoryPool&)
+			: restart(false)
 		{
 		}
 
-		Nullable<SINT64> start;
+		Nullable<SINT64> startValue;
 		Nullable<SLONG> increment;
+		bool restart;	// used in ALTER
 	};
 
 	struct AddColumnClause : public Clause
@@ -1323,7 +1325,7 @@ public:
 			  constraints(p),
 			  collate(p),
 			  computed(NULL),
-			  identity(NULL),
+			  identityOptions(NULL),
 			  notNullSpecified(false)
 		{
 		}
@@ -1333,7 +1335,7 @@ public:
 		Firebird::ObjectsArray<AddConstraintClause> constraints;
 		Firebird::MetaName collate;
 		NestConst<ValueSourceClause> computed;
-		NestConst<IdentityOptions> identity;
+		NestConst<IdentityOptions> identityOptions;
 		bool notNullSpecified;
 	};
 
@@ -1384,7 +1386,7 @@ public:
 			  defaultValue(NULL),
 			  dropDefault(false),
 			  dropIdentity(false),
-			  identityRestart(false),
+			  identityOptions(NULL),
 			  computed(NULL)
 		{
 		}
@@ -1393,9 +1395,7 @@ public:
 		NestConst<ValueSourceClause> defaultValue;
 		bool dropDefault;
 		bool dropIdentity;
-		bool identityRestart;
-		Nullable<SINT64> identityRestartValue;
-		Nullable<SINT64> identityIncrement;
+		NestConst<IdentityOptions> identityOptions;
 		NestConst<ValueSourceClause> computed;
 	};
 
diff --git a/src/dsql/parse-conflicts.txt b/src/dsql/parse-conflicts.txt
index b0587cd258..20cc527f2d 100644
--- a/src/dsql/parse-conflicts.txt
+++ b/src/dsql/parse-conflicts.txt
@@ -1 +1 @@
-44 shift/reduce conflicts, 17 reduce/reduce conflicts.
+45 shift/reduce conflicts, 17 reduce/reduce conflicts.
diff --git a/src/dsql/parse.y b/src/dsql/parse.y
index cc97817454..491d0a9805 100644
--- a/src/dsql/parse.y
+++ b/src/dsql/parse.y
@@ -2149,7 +2149,7 @@ column_def($relationNode)
 					newNode<RelationNode::AddColumnClause>();
 				clause->field = $2;
 				clause->field->fld_name = *$1;
-				clause->identity = $3;
+				clause->identityOptions = $3;
 				$relationNode->clauses.add(clause);
 			}
 		column_constraint_clause(NOTRIAL($<addColumnClause>4)) collate_clause
@@ -2200,7 +2200,7 @@ identity_clause_options($identityOptions)
 %type identity_clause_option(<identityOptions>)
 identity_clause_option($identityOptions)
 	: START WITH sequence_value
-		{ setClause($identityOptions->start, "START WITH", $3); }
+		{ setClause($identityOptions->startValue, "START WITH", $3); }
 	| INCREMENT by_noise signed_long_integer
 		{ setClause($identityOptions->increment, "INCREMENT BY", $3); }
 	;
@@ -3927,23 +3927,16 @@ alter_op($relationNode)
 			clause->dropDefault = true;
 			$relationNode->clauses.add(clause);
 		}
-	| col_opt symbol_column_name RESTART with_opt
-		{
-			RelationNode::AlterColTypeClause* clause = newNode<RelationNode::AlterColTypeClause>();
-			clause->field = newNode<dsql_fld>();
-			clause->field->fld_name = *$2;
-			clause->identityRestart = true;
-			clause->identityRestartValue = $4;
-			$relationNode->clauses.add(clause);
-		}
-	| col_opt symbol_column_name SET INCREMENT by_noise signed_long_integer
-		{
-			RelationNode::AlterColTypeClause* clause = newNode<RelationNode::AlterColTypeClause>();
-			clause->field = newNode<dsql_fld>();
-			clause->field->fld_name = *$2;
-			clause->identityIncrement = $6;
-			$relationNode->clauses.add(clause);
-		}
+	| col_opt symbol_column_name
+			{ $<identityOptions>$ = newNode<RelationNode::IdentityOptions>(); }
+		alter_identity_clause_options($<identityOptions>3)
+			{
+				RelationNode::AlterColTypeClause* clause = newNode<RelationNode::AlterColTypeClause>();
+				clause->field = newNode<dsql_fld>();
+				clause->field->fld_name = *$2;
+				clause->identityOptions = $<identityOptions>3;
+				$relationNode->clauses.add(clause);
+			}
 	| col_opt symbol_column_name DROP IDENTITY
 		{
 			RelationNode::AlterColTypeClause* clause = newNode<RelationNode::AlterColTypeClause>();
@@ -4082,6 +4075,23 @@ alter_data_type_or_domain
 		}
 	;
 
+%type alter_identity_clause_options(<identityOptions>)
+alter_identity_clause_options($identityOptions)
+	: alter_identity_clause_options alter_identity_clause_option($identityOptions)
+	| alter_identity_clause_option($identityOptions)
+	;
+
+%type alter_identity_clause_option(<identityOptions>)
+alter_identity_clause_option($identityOptions)
+	: RESTART with_opt
+		{
+			setClause($identityOptions->restart, "RESTART");
+			$identityOptions->startValue = $2;
+		}
+	| SET INCREMENT by_noise signed_long_integer
+		{ setClause($identityOptions->increment, "SET INCREMENT BY", $4); }
+	;
+
 %type <boolVal> drop_behaviour
 drop_behaviour
 	:				{ $$ = false; }