Hmm, not all airline FFPs have change restrictions. US doesn't restrict changes for awards on QF (at least not this past July) and the changes on my CX140A award from AA seems t be free of restriction. If I reticket my current itinerary, I even get a refund on taxes!

But as Andrew Webber says, BA EC sucks. Any change in flights results in a reissue with reissue fees.