I owe my old baal dira some money and my old job owes me money. Can I tell my baal dira to collect it from my old boss?
Although Shibuda de-Rabbi Noson allows the baal dira to collect the money from your employer (see Shach 86:3 who applies the concept even to sechirus poalim, but see Shoham VeYashfeh (of the Tehilla LeDavid) on the Rambam, Avadim 3:15), but you cannot shirk your responsibility from him by telling the baal dira to go to the boss.
Paying the baal dira remains your responsibility, and you have to ensure that he receives the money from your boss. If he doesn’t, you remain obligated to pay him.