Split database question

I have a split database with the linked tables set up on our server so everyone has access to them. My problem is, I need to link 2 of the tables together for a query but they have a mismatch in the design, one has number and the other has text. I want to change them both to number. I haven’t yet tried to get everyone off so I can try and go in to the server with nobody on (real pain trying to keep everyone off. Will this work or will I have to change everything in a backup program and split it again? Thanks…Mark