Originally Posted by moral_low_ground

Just to clarify - assuming date changes are free - I presume that as the ticket is (just) being revalidated then they do not recalculate taxes etc and so costs in all circumstances to change a date are zero/free.

If they (BA) decided to re-issue the ticket would that involve a re-calc of taxes which (due to variable exchange rates) is bound to lead to a minus or a plus from the original calculation. In this case - and if taxes increased - would BA have a case to ask me to pay them ? given that the date change is free but increase in taxes needs to be paid