I've been stumped by this twice. I'm with a party in Moorcroft Manor, and someone takes the down elevator, presumably checking the "invite" buttons for the rest of us. I get the message, "Your party member [name] has gone on ahead; if you're quick, you can join them!" So I run to the elevator and descend... and wind up alone.

I'm guessing that I ought to have gone into the Social menu, clicked the party member's name, and found a "Join" command. But can someone confirm? I don't really want to just experiment since that costs a bit of elevator CE, you know?

(Neither time this happened could I get any party member to answer me when I asked, "What should I have done?" And I can't seem to find this topic discussed anywhere in the wiki or the forums. If this is covered elsewhere, sorry for the redundancy and just point me to the right webpage. Thank you!)