I forgot to look this up at work today. I believe this is the bulletin:
#99-00-89-019W: Global Warranty Management (GWM) Warranty Parts Center (WPC) Parts Return Program Information - (Jan 28, 2022)
You will find this in Service Information. Section "R" is what you are looking for. But as always, where GM warranty is concerned, you should be familiar with the entire document.
This procedure gets messy if you have crating costs and a core. The system currently doesn't allow both as the bulletin states. There are ways but it takes approval and your service rep.
This is not too difficult, just takes a lot of time the first time. As Zep said you do have to have someone (or you) watch the credits to make sure they go to the right place. Including the $25.00 you will get for doing this. Don't spend it all in one place.