A returning resident visa is intended for Green Card holders who have lost their Lawful Permanent Resident status because they have stayed outside of the USA for too long. The Green Card holder can apply for a returning resident visa while outside of the USA. Be aware that applying for this visa means repeating the entire Green Card application process. Furthermore, the applicant must have a very good reason for not having returned to the USA. An example would be an illness that prevented the holder from traveling to America.
Re-Entry Permit - I-131
A re-entry permit is a document that allows a Green Card holder to re-enter the USA after an extended stay outside of the country. The travel document allows the US immigrant visa holder to stay outside of the USA for a total of two years with no negative effects to their Green Card status. The application (Form I-131 Application for Travel Document) must be submitted and processed in the USA.