Use the owner's key.
On the other hand, if you are having problems getting the car to respond properly to your key (unfortunately you didn't seem to think it was important to actually tell us what the real problem is), these may help:
http://www.rac.co.uk/forum/showthread.php?16411-Suspect-immobilizer-fault-on-my-Renault-Scenic
https://www.youtube.com/watch?v=DoPfLZPrPDg
http://www.justanswer.com/uk-car/2fspq-renault-megane-scenic-replaced-battery.html
http://www.remotekey.co.uk/renault/renault-immobiliser-faqs/
http://www.renaultforums.co.uk/showthread.php?t=15228
XXXXX, October 2015
