Google Prior service business rules. Scroll down to line 7d. E1-E4 with less than 36 months active federal service can join as needs of the Army. Get that 368 signed, DO NOT pin SGT, and he'll be good to go to join with a new MOS at the needs of the Army (usually 5-10 on the list when they go to MEPS, but you cannot choose from the Recruiting Center for PS options).
E-1 to E-4 with less then 36 months of Active Time can enlist RA as long as he has a 368 from the unit. He would first need to speak with his COC and see if they are on board to release him. Then he needs to speak with a recruiter to get entered into the system for the 368 to be generated or the recruiter can hand jam a 368. Also a 4187 has to be done, which states other criteria the soldier must continue to meet prior to shipping to their gaining unit. Once all the I's are dotted and T's are crossed. The Soldier must go back to MEPS to pick their job for RA. Sometimes the Soldier get's lucky and is able to stay in their MOS or they have to pick what the Army is looking for right now based of their ASVAB/Line Scores.
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