The Erase All option, deletes the calls you have selected to log. See Setting Which Calls are Logged.
Caution
•This action also deletes all speed dial entries and phone personalization options. See Default Phone/Erase All Settings.
To erase all logged calls:
1.Press 
Log and then press More.
2.Press Delete. You are presented with a message asking you to confirm that you want to delete all entries.
3.To remove all logged entries, press Erase.
Note
•Loss of power to the phone will cause all call log entries to be deleted.