I believe you answered below questions earlier but i was not able to follow, can you please answer below again?
When you pay i94 fee online, should we give the old passport details or New passport details?
Once the i94 gets extended, will I be able to check my i94 using new passport number or old one?
If we are asked to cross the border, can you please explain the steps we need to follow?
Thanks a lot for your help,