Guru's Guide to SQL Server™ Stored Procedures, XML, and HTML, The

Altering Stored Procedures

Just as you create stored procedures using the CREATE PROCEDURE command, you alter them with ALTER PROCEDURE. The advantage of using ALTER PROCEDURE to change a stored procedure is that it preserves access permissions, whereas CREATE PROCEDURE doesn't. A key difference between them is that ALTER PROCEDURE requires the use of the same encryption and recompile options as the original CREATE PROCEDURE statement. If you omit or change them when you execute ALTER PROCEDURE, they'll be omitted or changed permanently in the actual procedure definition.

A procedure can contain any valid Transact-SQL command except these: CREATE DEFAULT, CREATE FUNCTION, CREATE PROC, CREATE RULE, CREATE SCHEMA, CREATE TRIGGER, CREATE VIEW, SET ...