Amex plat/priority pass have access to what I call the generic lounges.
This is a YMMV topic. Some reps at the lounges dont know the difference between the US cards and Asian/European ones.I was once guested into the Plaza Lounge at YVR with such a card.
in europe they dont care about my credit card. they want to see a priority pass...
What airline?
I too will be stopping in Frankfurt for a few hours. I dont have the CC - is there anything else to be done?
if you are lucky, and subscribed to my promo, and you have it on time, or meet a guy like me in FRA, who invites anyone that looks yiddish into the lounge.