In the event that you are not making alterations on time then you should have to pay Virgin Australia Change Flight Fee. Assuming you are bombed in doing changes inside 24 hours then you should pay limited quantity of 100USD. Assuming that you have ticket protection then you are qualified for making changes 72 hours before the takeoff of flight. If pessengers are making changes by visiting at the air terminal or by the call then they should pay 50 to 100USD change fee.

https://airlinespolicy.com/flight-change-policy/virgin-australia-flight-change-policy/