My parents got a one-year multiple entry B-2 visa last year and were granted a six-month for staying in USA at airport. Their current status will expire soon (but their B-2 visa is still valid till summer), and we are trying to renew their status. My question is what is the best way.
1. Apply for extending with form I-539.
2. Visit Canada for 1-week then come back.
XBT, PJiang, and others, please help me. Thanks so much in advance.