Do you need orders when doing an interpost transfer?

If it is part of the same reporting HQ, no. If it is a different organization, yes. It is as simple as codes in the system but requires a paper trail. Thank you for your service.

Talk to you HR guys. (Personnel). You have to sign in somewhere.

If it's within the same MACOM or HQ, the higher unit produces a 4187 directing a move, or else orders directing an interpost transfer. If it's outside the MACOM, for instance, FORSCOM to USASOC, HRC has to place you on assignment and you will PCS (no-cost PCS) to the new unit through the usual levy process.

Anytime you are transferring whether it is between units on the same post, to a new post, to attend leadership training, etc. If you do not have orders find out why, and do not go without the orders in hand. And keep copies (at least 2 hard) of everything. Once the paperwork is approved the losing post should cut the transfer order within the same unit no orders but to a different unit (even within the same BN yes, you need documentation for darn near everything. Good luck and bug the heck out of people.