Can someone travel internationally while their adjustment of status (I-485) application is pending, and what documents are required to avoid abandoning the application?

Yes, in many situations a person with a pending Form I-485 may travel internationally, but they generally must obtain Advance Parole before leaving the United States. Advance Parole is issued through Form I-131 and allows an applicant for adjustment of status to return to the U.S. without the application being considered abandoned. If a person departs the country without Advance Parole while their I-485 is pending, USCIS may treat the adjustment application as abandoned unless the person holds certain dual-intent statuses like H-1B or L-1 and returns using that status. It is important to carry the Advance Parole document, passport, and adjustment receipt notices when traveling.

They need to get an advance parole document before traveling to avoid complications with the pending application