A few questions in relation to this (have changed these tickets previously but only for dates).

1. If one changes (before outbound flight FWIW), can one change the origin and destination, with the fare paid treated as a credit? e.g., I am currently ticketed XXX-VCE.TUN-XXX. Was originally going to book from a nearby airport but could not use a credit voucher as there was a couple of very short WS flights involved. Say I want to change the outbound to arrive in VIE, and the origin to XXS, would this be allowed?

2. If I want to change just the date for the outbound before travel commences, am I right to assume that both outbound and inbound fares are priced at the prevailing available fare? e.g., if I want to change the outbound but the inbound has increased in price, I will have to pay the higher fare for the inbound? Or do I get to keep the cheap inbound?