The reason to go back to country of origin would be family related, unwell elderly parents, etc.
How long do you need to be out of the country for?
You can apply for reentry permit if you wish.
Yes you can be sponsored for another one, not through the person who sponsored you for the first one, assuming it was family member.
You are welcome to use the link provided to contact me to discuss your case if you wish.
Yes, you can refile. You have to explain why you abandoned your previous residence, but that should be easy to do. Also as the other response says, you can file a reentry permit that allows you to stay out of the US for upto 2 years.
The above responses are both correct. One additional fact you need to know is that you must file the application for a ReEntry Permit while you are still in the US, and you must remain in the US long enough after filing to complete Biometric processing so that your applicaiton can be approved.
This is general information only. It is not intended as a substitute for legal advice and does not create an attorney-client relationship.
Depending on how many years you plan to be abroad I would not lightly give up the green card and woudl recommend a Reentry Permit instead which would allow you to be overseas for up to two years for the first few and later granted a year at a time. If it does appear better to give it up then you can be re-petitioned at a later date but would not get the benefit of your older Priority Date since PR was granted from this already.
Lynne R. Feldman, Attorney at Law
Concentrating in Immigration and Nationality Law
2221 Camino Del Rio South, Suite 201
San Diego, CA 92108
phone: (619) 299-9600, facsimile: (619) 923-3277
Formerly Adjunct Professor -- Immigration law
University of Illinois College of Law