Does the USMC DEP contract expires in 365 days?

I want out of the USMC DEP because i want to join another branch. However, I heard that to join another service. I'll need a discharged letter n a wavier? However If my DEP contract expires in a YEAR, do i still need a discharged letter? Is it true that the USMC DEP contracts expires within 365 days? (I read something like that from an online source)