The phone's redial operation can work in either of the following modes:

Open Call Log
If this mode is selected, pressing Redial will display a menu of the most recent outgoing calls in your call log. You can select the call that you want to redial and perform a number of other functions.
Last Dialed
If this mode is selected, pressing Redial will immediately repeat the most recent outgoing call in your call log. None of the other redial functions will be accessible.

 

You can select the redial mode that the phone uses. In either case, the redial function uses the outgoing call records in your personal call log. If you delete the records in your call log, redial will not work until new outgoing call records exist in your personal call log.

Note: Use of a centralized call log can be switched off by the system administrator. In that case the numbers used for the redial function are stored by the phone. This guide only covers redial using outgoing call records in the user's centralized call log.