Return flight modification and costs.

[rgbrock1]

Hi.

I"m not sure if this is the correct forum in which to post this question but I'm sure the moderators will move it if it isn't!

My wife and I are flying to St. Thomas USVI next week. We're initially staying for 7 nights but I have this sneaky suspicion (!!) that we'll be prolonging our stay for 1 or 2 more nights. (We're flying with USAirways).
Does anyone have any tips on how to obtain the cheapest rate for a modification in a return flight?
Thanks in advance.

[Capetonian]

It depends primarily on the penalty rules pertaining to the fare type you purchased, the rule of thumb being that the less you paid the less flexible the ticket will be.

It also depends on the attitude of the ticket office people when you ask for the change, but these days there is not a lot of flexibilty shown.