Resigning

I am currently a full-time Clerk (regular since 2018) with 5 years of prior military service. I've been trying to e-reassign to another district within the state for the past 1.5 years. I am moving this summer and plan to resign from the P.O. if I can't get a transfer approved. My question is: will I be able to get rehired with time in service if I reapply and come back to the P.O.? Or will I have to come back as a PSE? I know I will lose seniority but that is the least of my worries.