Beginning July 1, USCIS will no longer accept Form I-407, Record of Abandonment of Lawful Permanent Resident Status at international field offices by mail or in person. Individuals who wish to voluntarily record abandonment of their lawful permanent resident (LPR) status must submit Form I-407 by mail to USCIS Eastern Forms Center in Williston, VT. Processing times will be within 60 days, which does not include mailing time to or from outside of the United States.
Source: AILA Doc. No. 19061735.