This may be one of the dumbest questions that you have heard here but is it at all possible to change out a remodel valve/plate without turning off the water supply?

I want to remodel my second bath and for the shower just want to replce the tile and fittings. The problem is that I live in a condo building with no separate hot/cold water shutoffs. So if I shut off the water supply I will shut it off to 4 units.

During the remodel, I was planning on keeping the current single water control valve/cover plate on while I tile most of the shower and then taking off the valve/plate at the end, finishing the last few pieces of tile, and then replacing with one of those Symmons valve/plate remodel combos that you see at Lowes.

Here comes the stupid question.......can you take off the valve/cover plate without turning off the water supply - i.e. not taking out cartridge, clip or anything else.

I'm sure that the best way to do this is to just turn of the water for an hour or so and have individual shut-off installed to the shower in my condo but access is not easy and was wondering if there was another way.