I asked for my Peretti initial to be switched onto an 18 in, and she told me there would be a charge. If I go back ask someone else, they should do it for free?
Which initial do you have? Some (or all of them I can't remember) need to be cut and resoldered. It depends on the initial I guess, I know with letters like "Y" you can't take off the chain. Other letters like "A" may be removed easily I think.