Provided the pins come out ok, then they can go back in. The problem is when the pins get stuck they either bend coming out or have to be cut out, either way you'll then need new pins.
Someone like RS Tuning will know what they're doing, and if anyone will get them out OK, they will. However; if the pins haven't been out in a while and the brakes haven't been cleaned regularly then there is a chance they could be completely stuck, in which case they WILL bend/need cutting (regardless of who is doing the work).