Out of US stay of more than a year on GC?

[javaxmlsoapdev]

My mother recently got her green card on relative basis (USC sister). She is flying to India in few days and not planning to come back for next 2 years. In order to get permit(to stay out of US for more than a year) from USCIS, which form I should fill up and send to INS? I believe this needs to be done before she leaves US? Please advise.

 

[amishah]

My mother recently got her green card on relative basis (USC sister). She is flying to India in few days and not planning to come back for next 2 years. In order to get permit(to stay out of US for more than a year) from USCIS, which form I should fill up and send to INS? I believe this needs to be done before she leaves US? Please advise.

Form I131