Any lovely GTers know anything about getting an antique ring re-set?

Mr.TenInch asked my parents for my grandmother’s ring over New Years. The diamond was chipped a long while back, and the (brand name chain) jeweler told my dad when he tried to get it re-set he would need to find a jeweler that specializes in antique settings to get a replacement diamond set.

I have absolutely no idea how to go about finding a specialty jewelwer/how to know if a jeweler knows their stuff and won’t damage my grandmother’s ring/how much I should expect to pay for such a service? Any one have any ideas/pointers?