I recently called to change a non-refundable ticket on CO and was told there was a $100 change fee, and when they repriced the fare it came out $44 higher, so was expecting to pay $144 in addition to the $189.50 I'd already paid. I gave the res agent my credit card number, and on my receipt which I picked up at the airport, it shows a total of $233.50 and a second amount of $44 (with taxes) in addition to the $189.50 already paid (i.e. 2 line items on the receipt).

Where does the $100 usually show up? Should my receipt have shown $333.50 if it were charged? I also can't find the $100 charge to my credit card, which leads me to believe they may have overlooked the $100 change fee (or waived it or whatever). This was the first ticket I've ever tried to change, so I don't know where to expect the $100 to show up.....

Normally, the total additional payment shows up as a single amount, called an "add collect". It comes at the end of the "linear fare calculation", the long list of routings, fares, and fare basis codes just following the form of payment in the middle of the passenger receipt. The add collect is abbreviated A/C. In your case, it sounds as if the agent made an error and collected $44 twice instead of $44 once and $100 once.

Thanks! She only collected $44 once; I was only repricing the return trip. I see the A/C notation, my credit card info, and then the charge + tax = $44.00. Looks like she forgot. :-)