There is. You should try to see through what the manager has in plan. If its a case of negotiation it might work. But if you are nothing more than a work donke

There is. You should try to see through what the manager has in plan. If its a case of negotiation it might work. But if you are nothing more than a work donkey to him, and he likely has other pets at office who will receive his favors regardless, just take the new offer and leave.