Well, on any shower, you can remove the handle and then the chrome escutcheon plate, just leaving the valve body in the wall...intact, with cartridge in place.
How old is the existing valve? Because if you retile, you are committing to another ..20 or so...years on that valve. Most of us would recommend installing a new valve at this point, unless it is fairly new.
One issue.....it sounds like you are replaceing tile with tile...so the location of the valve in the wall might be good. If you use a different thickess of substrate or tile, you could affect the proper fit of the trim and handle.