You can remove an integrated login mapping using either Sybase Central or Interactive SQL.
Connect to the database as a DBA user.
Open the Login Mappings folder.
In the right pane, select the login mapping you want to remove, and then choose File > Delete.
Connect to the database as a DBA user.
Execute a REVOKE INTEGRATED LOGIN FROM statement.
The following SQL statement removes integrated login permission from the Windows user pchin.
REVOKE INTEGRATED LOGIN FROM pchin
See REVOKE statement.