You can remove euro locks without the key, but I can't tell you how to I'm affraid, otherwise every one will be burgled. A qualified locksmith or double glazing firm can or should be able to do it, the last answer is incorrect.
Burt, November 2009
sorry! you cant do this without open the door. the lock has a screw that is inserted along the joining edge of the door. the screw is used to secure the lock in place and you will also need the key to remove the lock once the screw is out!! try this site for a better explanation http://www.practicaldiy.com/carpentry/euro-lock-cylinder-replacement/euro-lock-cylinder-replacement.php
