-555 AN AUTHORIZATION ID OR ROLE CANNOT REVOKE A PRIVILEGE FROM ITSELF

Explanation
  An authorization ID or a role
attempted to execute a REVOKE statement in which that ID itself appears
as one of the entries in the list of authorization IDs or role names
to be revoked.
  An authorization ID or a role cannot REVOKE
its own privilege. However, if SQLRULES(STD) is in effect or CURRENT
RULES contains STD, REVOKE from self is allowed.

System action
  The statement cannot be processed. No
privileges were revoked.

Programmer response
  Take one of the following
actions and reissue the REVOKE statement: 
Remove the authorization ID that issues the REVOKE statement from
the list of authorization IDs to be revoked.
Issue the REVOKE statement from a different authorization ID.

SQLSTATE
  42502