Changing Advance Tickets

[Essexman]

I have booked First Class Advance tickets (£13 each way) from London to Sheringham, but need to change to the next day. The same fare is available for the next day.
They were booked on East Coast but the 'amend' icon will not activate. I haven't picked the tickets up from the machine yet.

1. How to I change them?

2. Do I have to pay a fee to change both ways as they are singles, even though bought & changing together?

Thanks

 

[yorkie]

1) A station can do it.

2) Yes, that's right. (though the charge is at the discretion of the ticket office, you never know you might get someone who only charges one admin fee, but I do not want to get your hopes up).