I don’t think you can label her as “inconsiderate”. Or “making him work on his day off.” You don’t know exactly why rep agreed or how their conversation went but it was ultimately his choice to do so.

I don’t understand the dilemma. Just give her a ride unless you aren’t available. I find it interesting that you think she’s inconsiderate but you don’t think it’s inconsiderate to go back on your words after you promised her a ride.