I received a new BCBS plan through my employer that began at the beginning of the month, but I have not yet received a new ID card. I have a Dr appointment in a few days. How do I look up my member # and other info?

I received a new BCBS plan through my employer (I have had a plan through them for a few years, but this one is a different type / level) that began at the beginning of the month, but I have not yet received a new ID card. I have a Dr appointment in a few days. How do I look up my member # and other info? The app and online portal only show that the previous plan I had is expired; they do not show the new plan yet.