Thanks for the reply, lidosjawn. I just tried to use the "Change Flights" option, hoping to add the other passenger. But after I clicked both flights of the round trip to change, it sent me back to the round trip booking page. I could change the dates as long as I was booking another round trip, but I could not just look at one way flights, nor could I add any passengers. Unless it was just another Frontier website glitch --certainly possible -- I was limited to only changing my dates for a round trip flight, and just for me.

Well, I saw on the top of the homepage that Frontier was advertising no change or cancel fees through September 30th. Of course this could be interpreted in two different ways...

One, no fees for any flight changes up to and beyond September 30th, as long as the change is completed by September 30th.

Two, no fees for any flight changes only for flights to be taken by September 30th, with flights taken starting October 1st and beyond ineligible for this fee waiver.

So I called just to verify, and the first option is the correct interpretation. I cancelled my October roundtrip booking, and booked my November one way with an additional passenger with the credit. No fees were charged that I can see.

I would hate to think that the airline is being intentionally confusing regarding these things; I really think it's more a matter of not realizing that they're not being very clear. They know what they mean, but that doesn't mean that *we* know what they mean...