Cannot drop a user that owns messages or data types

Error constant SQLE_USER_OWNS_MESSAGES_OR_DATATYPES
ODBC 2 State 42000
ODBC 3 State 42000
Severity 16
SQLCODE –614
SQLSTATE 55W05
Sybase error code 13632
Probable cause

You attempted to drop a user that is the creator of a message or user-defined data type. The message or user-defined data type must be dropped first.