How to toggle 1 and 2

Without using If..Then how do I switch back and forth between 1 and 2

If the value in a 1 I want to make it 2 on exit from sub and if the value is 2 I want to make it a 1 on exit from sub

Actually I do not know which value it will be (without looking, of course) but it will be either 1 or 2 and I just want to make it the other value