It's a good idea to, as otherwise you're not selling anything. But no, you don't have to renegotiate a deal. If the contract allows, you can exit. If not, you'll have to negotiate something, be it a settlement, or a new arrangement, but you don't have to renegotiate a sales deal if you don't want to sell. Different subject. Apple insisted on a price matching agreement. That definitely strays into anticompetitive territory.