Had to dig back for this thread, but today I wasn't able to call in so I thought I'd try clicking through to the change button and see if it worked on an Aeroplan booking with a PR applied. Well, blew me away but it just worked. No fuss at all, recalculated the PR discount and let me pick new flights summarizing the changes. Anyway, small thing but made my life a little easier.

As an aside, apparently in July the AE call centre is shifting to 5am - 3am PST hours. Much better coverage than before.