What should someone do if they report to their next unit and their rank the system does not reflect their demotion after an Article 15?

I know I've been retired form the Army for about 90 days now. But im pretty sure they haven't changed the Army values in that time-frame. I'm pretty sure one of those Army Values is Integrity. It might take some time for all of the paperwork to catch up. If your "battle" has a shred of integrity, he will report wearing his new rank. It wont be pretty if you. i mean your "battle" are found out later on to be wearing the wrong rank. INTEGRITY is your answer

First is to check does it reflect in ALL systems or just one. Does his LES match the ERB? If one is different then the rank change hasn't flowed through all systems and his S1 can fix that. If nothing has changed at all he will want S1 to do the reduction sooner than later. Unless he's about to PCS someone will catch it when he hits the promotion eligibility roster again. When they back date his reduction he will incur a sizeable debt to the Army that gets worse the longer he goes without addressing it. If he's past the RCP for his new rank then his ETS needs to be changed as well.

Answer depends on if the SM has integrity or not.

If they do then they go see their S1 about the problem. Sure it is screwing themselves but look at it is like this. The SM is getting paid and with all monetary benefits tied to their rank. So let's say they get demoted in December. Flags are lifted and they PCS to a new duty station and it takes 9 months for the Army bean counters to catch the problem. First thing that is going to happen is everything is going to be retro-active to the date of loss so for 9 months and change they will have that pay at the former grade docked to coincide with their new rank. This includes BAH, BAS and all other grade reflected money.

This is taken out at the Army's convenience, meaning they do not care if they leave you a single penny. They can take it right then and there or in as many payments as it takes to get it back in whole.

Next, the SM will be counseled as they KNEW they had been demoted and did nothing. That can and should result in another UCMJ action and likely another demotion.

If they don't have integrity then they simply roll on, roll the dice and hope that the Army does not catch the screw up. Good luck with that.