Originally Posted by carrotjuice

Yes stopovers exceeding 24 hours can only be booked by phone.

Essentially, rebooking is something that does not require the cancellation of old ticket and reissuing of new ticket.

Say you book XXX - HKG - YYY where HKG is transit of less than 24 hours. Some examples:
- To change date and time of XXX - HKG - YYY is rebooking if HKG transit is still less than 24 hours.
- But if HKG transit is now changed to over 24 hours then it effectively becomes XXX - HKG and HKG - YYY hence it's reissuance. Likewise vice versa, from transit of more than 24 hours to one of less than 24 hours.
- If you change to XXX - YYY direct bypassing HKG, then it's reissuance.
- If you reroute to XXX - AAA - YYY by going via AAA and not HKG, again it's reissuance.

If return ticket XXX - YYY - XXX, changing date or time of either XXX - YYY or YYY - XXX is rebooking.