Changing Standard Error Codes

Is there anyway to change the error codes defined in the STANDARD package? ie: I'd like to reword the unique constraint violation description. Is this possible?

You could trap them and then display whatever error you want.

Can you give me a little direction on how to do that?

Try using INIT_PRAGMA
I'm giving an example
DECLARE
deadlock_detected EXCEPTION;
PRAGMA EXCEPTION_INIT(deadlock_detected, -60);
BEGIN
...
EXCEPTION
WHEN deadlock_detected THEN
-- handle the error
...
END;