Are you allowed a second change of mind after you've:
1) Exchanged your Advance through CC's procedure?
2) Had an Advance excessed through the industry standard procedure?
Re (1) - I have changed an Advance - or a series of Advance tickets, depending on how you look at it - multiple times with no admin fee using Crosscountry's website. To be honest I was expecting it to kick up a fuss eventually (a message along the lines of
'are you really this indecisive'!), but it didn't. I can imagine that if for some reason I needed the assistance of a human agent, they may have been a bit less willing - or possibly just very confused (looking at all the different booking references)!
The Crosscountry site is a Trainline-powered booking engine, and as far as I can see the system for changing an Advance ticket is the same as for all Trainline-powered sites (albeit crucially without the £10 admin fee). I understand it is called
'refund and reissue' - specifically the system has you buy the new Advance ticket at the full price (and this is charged to your payment card), then you are refunded the price of the original ticket to your payment card (either more or less immediately if you haven't collected it yet, or some weeks later if you have collected the ticket and need to post it in for a refund). It's a bit clunky, but it works. I have only done this on XC when paying with a credit card, but I'm guessing that even for an 'instant' refund the money might not be in your bank for a few days.
Also not quite sure what happens if you pay for the amended ticket using a different payment card - I'm guessing the refund goes to the original payment card (which would make sense to me), but I could be wrong.
The Trainline system does seem to ignore the 'same TOC' restriction when changing an Advance - possibly an unintended consequence of their
'refund and reissue' method rather than excessing the original ticket.
Lastly Crosscountry do state (
here) that you can only change your Advance ticket without an admin-fee up to 24 hours before your travel time, but that hasn't been my experience in practice - rather I've found you can change it right up to the minutes before departure time (quite possibly the very minute before departure time). However, I haven't done this for a little while so the situation may have changed.