I currently have a ticketed LONE4 with departure from SYD scheduled for September. I am considering a change in routing, but my TA advises that this will incur a reissue fee. My understanding of the most recent rule set is that for Areas 2/3 unlimited changes are allowed prior to departure, regardless of ticketing status. Can anyone clarify this?

If my TA is indeed correct, does making a stopover at a destination that is currently only transited class as a routing change? I am flying MEL-xLHR-TXL but it may be convenient to make a 'stopover' at LHR in order to connect to a separately-booked flight.

Thanks in advance!