Hi, this is my first post. I'm trying not to be a clueless newbie, and I did look in the sticky topics and in the Glossary, but cannot find what two common abbreviations mean: RDM and BIS. (I did find EQM which is the other one.)

Also, what is the difference between "C" and "D" fares (on United I guess)?

Much thanks and if this is the wrong place to post I apologize and please let me know. It might be nice to add BIS and RDM to the Glossary since I see them all the time.