The Marine Corps published its FY27 officer assignments process in MARADMIN 219/26. It covers career counseling, non-statutory boards, mover interviews, slating, and orders issuance for active duty officers. Paragraph 6 of the message states explicitly that it does not apply to the Marine Corps Reserve.
Bottom line: This MARADMIN is active duty only. Reserve Marines have nothing to act on here.
Who it affects
Nobody in the Reserve. SMCR, IMA, and IRR officers are all excluded. The message says so plainly in the final paragraph before release authority.
What you need to do
Nothing. This one is not for you. If you are an active duty officer or have questions about a pending activation that might put you into the active component assignment process, talk to your S-1 or monitor directly.
The official version
Source: MARADMIN 219/26. Released by MajGen Fridrik Fridriksson, Director, Manpower Management Division.
This is written by a reservist, for reservists. It is not an official publication of HQMC or MARFORRES. Always verify guidance with your command or unit S-1 before acting on any article or summary.