Display most recent Caller ID telephone numbers not old ones

How do you display recent callers ID telephone numbers. Our system seems to have stored/saved all old numbers. The most recent one I can locate was dated 5.6.09. So therefore how do you delete the old saved numbers making room for the most current callers numbers? Or better still can we set the phone to delete the oldest number each time a new call is received i.e overriding the old stored numbers with the new numbers. We have a KX-T7730 system.