A Lawful Permanent Resident (LPR, aka green card holder) may re-enter the United States with a valid Alien Documentation Identification and Telecommunication (ADIT) Stamp. It is also called an I-551 stamp, and it is temporary proof of lawful permanent resident status.
Generally speaking, LPRs can get an ADIT stamp at a USCIS Field Office by scheduling an appointment through the USCIS Contact Center. To get in touch with a Tier 2 USCIS representative, an LPR can dial 800-375-5283 to access automated information through an interactive menu 24 hours a day, seven days a week. LPRs can get live help from a USCIS representative Monday through Friday from 8 a.m. to 8 p.m. Eastern, except on federal holidays. The USCIS representative will typically only speak to the applicant or the sponsor, and they will need to have their receipt numbers available so the representative can verify their identity.
The Field Office asks that LPRs please bring (2) passport style photos OR a valid passport with them to the appointment.