CrossCountry trains on Advance Tickets notes:
Print your own tickets and m-tickets (via our Train tickets app) cannot be changed. Tickets collected from the station, a ticket machine, or sent by post can be changed with no administration fee. Sign into your account and select 'View my Bookings' and follow the steps to amend your journey.
This is different from the conditions for other TOCs, for example, GWR:
Advance tickets can be changed to a different time or date only - for a charge of £10 a ticket, plus any difference in the fare; if you choose a cheaper fare, the difference will not be refunded
The CrossCountry wording seems to suggest it applies to any train, not only trains operated by CrossCountry. However, Simon Calder writes in The Independent:
Rail passengers from Aberdeen to Penzance are set to benefit from the abolition of fees for amending Advance tickets.
…which suggests the rule only applies tickets that are (1) Advance, and (2) for journeys on CrossCountry trains.
Under what conditions can train tickets booked through CrossCountry be changed without paying an administration fee?
Must the travel be on CrossCountry trains, or does it apply anywhere in the country?