How can I re-establish a residency status?

With very few exceptions, a Permanent Resident who moves to Mexico and lives there for a couple of decades will be deemed to have abandoned his/her residence in the U.S. and to have abandoned Permanent Resident status. In that event, it becomes necessary to start over with a new application process, assuming eligibility exists. Some immigration law firms, including mine, offer legal services on a "flat fee" basis so that a client will know the total expense from the very beginning, and a few immigration law firms, including mine, offer an initial consultation free of charge.