Originally Posted by Simon Schus

(I am assuming you already have Global Entry on either an ESTA/VWP or a visa)

Yes, I’ve done thing from an ESTA to a Green card. You just turn up to any enrollmentnoffice without an appointment and tell them you need to change your details (make sure you tell them this otherwise they’ll expect you to have an appointment). It is quite simple and took me about 4’minutes after a 15 minute wait to be seen (I had to change my surname too with my marriage certificate in addition to updating to use the green card).

When entering the USA using your green card, you use the green card and not your passport. I can’t remember what way it goes in to face the scanner but mine never works anymore so I just type in my alien number instead and it works that way.

You are eligible as a green card holder to have a Global Entry Card though it’ll cost you $15 even though it would’ve been free when if you were a green card at sign up (I argued but didn’t work, and I had to order through the old GOES system). I ordered this because it was a useful federal ID that was appropriate as an ID for flying domestically, so I didn’t have to keep getting my green card out (or US state id/driver license which I haven’t organised yet).

Good luck!