I do not know how to do that. All she has to do is accept my challenge. Perhaps she is not playing
Southwest Chess Club - 3-round Game/60 (+ 5-second increment) (May 28, June 4, June 11)
I tried another challenge, but it said I could not because one of us was playing. I am not playing, so I do not know what to do.

Her profile is https://www.chess.com/member/elie-mae
From the top of that page, you can message her. She may have left. I think that next week we may revert to the usual Thursday night format. A lot of folks are having trouble connecting.

Ellen, Robin challenged you around 7:00 pm. This system was confusing to many of us. So, sorry for the missed game. I think we will do a different event next week. Sorry for any confusion!

Apparently the challenge comes up in a small window... easy to miss. Again, sorry for all this confusion.
Robin, can you message her?