How can I cancel an edit?

For instance.
Go to contacts, select a contact, and click Edit. Then select a field
and type a couple of characters, the contents of the field have
changed. Now select another field, and make changes, and so on...
Finally I simply want to DISCARD all the changes and NOT to save
anything. HOW CAN I CANCEL THE EDIT AND SIMPLY CLOSE THIS CONTACT
RECORD?

The "Undo" command doesn't undo everything. You got to undo one by
one, I did not see and easy way to tell when the undo has to be
stopped. And it is extremely error-prone, slow, and cumbersome.

It appears that it is true for any item that you edit. Excel, Word etc
etc, they all behave the same way. Once you edit, you have to save! Or
am I missing something so obvious?

BTW, my device is Cingular 8125 running Windows Mobile 5.0 ( OS
5.1.195 build 14928.2.2.0).

Thank you all for your time.
Tom