How REPLACE METHOD And CREATE METHOD Differ
You can perform CREATE METHOD only once to declare the body definition for a method. If you try to use CREATE METHOD a second time to define the body for an existing method, the request aborts and Teradata Database returns an error to the requestor.
Instead of using CREATE METHOD to redefine the method body, you must use REPLACE METHOD. REPLACE METHOD can be performed multiple times to replace the body definition for a method.