Likely cost of upgrading "K" PE to "S" or "W" PE?

Tried calling the FC this afternoon and couldn't get through, so thought I'd ask here;

I've got a PE ticket to LAX dep 3/6/11 returning 8/6/11 that's a K fare. Anyone got any idea at all what the likely range (as I know this is NOT an exact science!) of the cost of upgrading the K to an S (or W - but I assume the S would be cheaper) might be as I've got a ton of miles sitting in my account?

Thanks.

[Neil]

That is a tough question to answer as you will have a change fee plus the difference to the current S price. For the most accurate answer you are best calling FC, although you could price up an S/W on the website to get a rough idea.

Of course, the other thing is to make sure there is G availability to upgrade to with miles, otherwise it will be pointless upgrading your PE fare.

might be nest to give FC another go as they will check if there is a G available and if so they can book it straight away for you

You will pay a lot because you are less than 21 days advance for the S ticket so actually I think you may only be able to buy a W within 21 days (no advance).
Make sure you are sitting down when you call them.