Newbie - no cancel/esc button

Hi,
I've got a iPaq rx1950. Can anyone tell me how to cancel inputting something.

For example. If I edit an appointment and start typing over a few fields, is there any way I can abort what I'm doing and leave the appointment unchanged. I only see "ok" (which saves the changes). There's no "cancel" option .

I know about ctrl-z for undo and ctrl-q to exit app but they're not always appropriate.

Thanks,
Lee