Using existing wiring to run new wire
In order to pull new new wiring with existing wiring, the circuit would have to be in conduit. Assuming you residence is like most, your system is more likely to be Romex-type cable (NM). If this is the situation it can't be done because the NM is stapled to the framing. So if you talk to the contractor you might ask him about the easiest way to achieve your task.

Hope this helps.