I shipped a piece of gear already that was supposed to be turned in to CIF. What would the memo look like stating that this gear is shipped?

Go to CIF and ask them

Be prepared to pay for the item. I'm assuming the item is on the list of items that you cannot PCS with and that is why you're asking. If that is the case, CIF would not have to clear you until you either "find" the item or pay for it through a statement of charges.

Was it a PCS move? I don't know how it works with active duty, but you might be able to have your S4 shop assist you with cross-leveling that piece of gear between this outgoing base's CIF and your new post's CIF.

I know in the reserves, there is one central CIF warehouse that supports the entire reserve component. Soldiers draw their equipment at their first unit and turn it in when they leave service, It travels with them if they transfer. New equipment is added by unit supply as needed throughout their service journey, and old stuff gets turned in as needed. Right now I own two complete sets of battle rattle, rucksack, daypack and cold weather clothing. One in each pattern. I could, if I wanted to, keep all the crap until I leave and turn it into the supply of my final unit. However, I will turn in the old crap ASAP after COVID-19 restrictions allow it.