Ronnie,

Have done a bit of research on the Tricare Reserve(I'm Navy). I was told by my Tricare office that once your DEERS info has been updated to reflect your reserve status you can enroll in Tricare(reserve). I don't think you can pre-enroll if you will(Tricare uses Deers to verify eligibility). Like many other programs from DoD, this program has been implemented and sold to the customer long before the folks implementing it have been given the tools/resources needed to help the customer. If it were me, I would have the Tricare reserve forms ready to go the day I checked out and changed my DEERs info. Your coverage should be retroactive to the day you enrolled. Good luck.