thanks very much for the reply

yes a "T"

here are the conditions, verbatim.

"Time/date changes permitted at any time before each flight departure for a change fee of $ 200 or an upgrade fee of $ 200 plus any difference in fare. Changes subject to availability"

I read that as, a fare difference was applicable for an upgrade only.

but I'll bet you're right

in fact the more I read the conditions, the less clear it gets

thanks again