My father had applied for permanent residency in December 2016 but he left the U.S in March 2017 while his application was still pending. His application subsequently got approved in May 2017. Although he has been out of the country, there has been no communication from USCIS indicating his Green card is canceled or revoked. In January 2020, he applied for and received a B1/B2 visitor visa. He now plans to return to the U.S this month (mom is LPR). Is it better to try and enter with his GC at the port of entry with the visitor visa as backup or better to enter with the B1/B2 visa and present/surrender the Green card voluntarily?.