update RDB$PROCEDURES P set
   P.PRDB$PROCEDURE_SOURCE = null
where
   P.RDB$PROCEDURE_NAME = 'PROC_NAME'


update RDB$TRIGGERS T set
   T.RDB$TRIGGER_SOURCE = null
where
   T.RDB$TRIGGER_NAME = 'TRG_NAME'


update RDB$FUNCTIONS F set
   F.RDB$FUNCTION_SOURCE = null
where
   F.RDB$FUNCTION_NAME = 'FUNC_NAME'