Switching between Sema and Reta while waiting for more stock, or taking a break during stock refill waiting periods

[sterlingschrute]

TL;DR -- on a personal stock gap from Sema (waiting on source), but have Reta sitting around. Have been taking Sema for the better part of 2 years now. If I switch to Reta for the few weeks it may take to get more Sema delivered, would I have any trouble returning to Sema after? Would it be better for me to take a few weeks off any GLP to let my metabolism reset and have a break?