For instance, no, he would not have to be resigned before a deal is in place. Exact opposite actually. They would come to an agreement first, put it all down on paper, and then everyone would sign. The contract will actually stipulate the terms of the trade. It is an actual "sign and trade" transaction.
Which is also why I say this isn't going around the rules or anything of the such. It's an actual transaction that is purposely allowed.
In short, he will be a restricted free agent that will sign an already agreed upon contract to trade him.