Paperwork ques: Reduction of rank

[birdseye]

I'm having trouble locating guidance on what paperwork was required when a non-com was reduced in rank. Kautz' Company Clerk mentions noting reductions on the muster roll, and I assume a special order would be issued by regimental HQ. What form or letter might have ended up in the soldier's hands? What needed to be filed upstream to effect the change in pay? Thank you for any help you can give.

-Paul Canter