Source: https://dev-docs.nebula-graph.io/v5.3.2/database-gql-reference/procedures/alter/
Documentation version: v5.3.2

# ALTER PROCEDURE statement

The ALTER PROCEDURE statement modifies a user-defined procedure (UDP) in the used schema, including its name and comment.

To alter the input parameters accepted by a UDP without changing the name or procedure body, [drop the UDP](https://dev-docs.nebula-graph.io/v5.3.2/database-gql-reference/procedures/drop/) and create a new one.

To alter the procedure body without changing the name or input parameters, use [CREATE OR REPLACE PROCEDURE](https://dev-docs.nebula-graph.io/v5.3.2/database-gql-reference/procedures/create/).

Note

An operation involving a non-default schema or an object in it requires access to the schema, either implicitly or through an explicit `USAGE` grant, as well as the privilege required for the operation. The schema access check and the privilege check for the requested operation are independent; satisfying one does not satisfy the other. Schema access control does not apply to temporary graphs or built-in procedures and functions. For more information, see [Schema access control](https://dev-docs.nebula-graph.io/v5.3.2/server-admin/authorization/schema-access-control/).

## Prerequisites

- The UDP is created. For more information, see [CREATE PROCEDURE](https://dev-docs.nebula-graph.io/v5.3.2/database-gql-reference/procedures/create/).

- To alter a UDP, you must either be the owner of the UDP, be granted to perform the action `ALTER` on the UDP, or be granted to perform the action `ALTER ANY PROCEDURE` on the used schema. For more information, see [Roles and privileges](https://dev-docs.nebula-graph.io/v5.3.2/server-admin/authorization/).

## Syntax

diagramsource

 alter_procedure_statement parameter_declaration  

````
alter_procedure_statement ::=
    'ALTER' 'PROCEDURE' procedure_name '(' ( parameter_declaration ( ',' parameter_declaration )* )? ')' 
    ( ('COMMENT' new_comment_string) | 
    ('RENAME' 'TO' new_procedure_name) )

parameter_declaration  ::=
    parameter_name? parameter_type ('DEFAULT' default_value )?   

````

## Parameters

### `procedure_name`

The name of the UDP to be altered.

### `parameter_name`

The name of the input parameter accepted by the UDP.

### `parameter_type`

The data type of the input parameter accepted by the UDP.

### `default_value`

The default value of the input parameter.

### `new_comment_string`

The new description of the UDP.

### `new_procedure_name`

The new name of the UDP to be altered.

`procedure_name` must be an identifier. For more information about identifiers, see [Rules for naming identifiers](https://dev-docs.nebula-graph.io/v5.3.2/database-gql-reference/overview/keywords-identifiers/).

## Examples

### Alter the comment of a UDP

````
'''
// Create UDP `test1`
CREATE OR REPLACE PROCEDURE test4(a INT, b STRING) RETURNS (x INT, y STRING) COMMENT 'test_comment_1' AS { RETURN a, b }
'''

'''
ALTER PROCEDURE test4(INT, STRING) COMMENT 'test_comment_2'
'''

````

### Alter the name of a UDP

````
ALTER PROCEDURE test4(INT, STRING) RENAME TO test44

````