There are certain acts that can lead to one losing his or her permanent resident status and they are defined by Section 237 or 212 of the Immigration and Nationality Act. These acts may result in one being forced to appear before an immigration court.
Aside from these acts, there are a number of other ways for one to abandon their permanent resident status.
These include moving to another country with the intention of permanently settling there, staying outside of the US for a year without obtaining a re-entry permit and remaining outside of the country for two years after being issued a re-entry permit without procuring a returning resident visa.
There are two other ways that one can lose his or her permanent resident status and they both involve income tax returns. The first is by simply not filing income tax returns while living outside of the country for any length of time and the other is by declaring oneself a “nonimmigrant” on one’s income tax return.