Flight change?

i have a return trip booked to australia (sydney) flying out the 3rd of sept and returning the 7th of 0ct.

i have a distinct feeling i may need to come back before then, what will the situation be if i need to change my return flight? what will the cost be etc?

(it's an e-ticket)

many thanks!

[mcmbenjamin]

Oh the cost...

Many factors go into the change cost. What is the fare class?

it's economy... is that what you mean?

[Nottingham Nick]

As you have asked the same question in two forums, this may lead to two confusing threads running together, so I will lock this one.

It is only necessary to post a question once. There are lots of people here who will help.

Nick