I have a question related to the change rule. I was about to start a new thread about it, but since this thread has been started, I decided to make use of it to ask.

What constitutes a change and what requires a complete re-issue of a ticket?
For example. I want to book a one way ticket between zone 3 and zone 1. Let's say I do book a DEN-FRA-CDG. I presume that changing the date of the whole ticket (no stopover allowed) would not require to re-issue and simply I would have to pay 20 pounds for the change. On the other hand, I am not clear of what would happen if I wanted to change so that I do DEN-FRA-DUB for example. Would that be a change covered by the 20 pounds of change fee? That way when I make up my mind about which one of the two destinations I want to go to, I would not have to release the DEN-FRA which is the toughest part of the itinerary to get.

Any experience?