Soldering

My engagement and wedding band is soldered currently. Can this be un-soldered somehow if I want to change my setting in the future?

[Metalman]

Yes with care,  this is one of those kind of things you will want to have a skilled bench jeweler handle - not something for your friend, the silversmith, down the block.  Gold handles somewhat differently, the kind of retooling you are referring to is done all the time in the commercial jewelers trade.