Lexus CT200h Owner's Manual page 446

3-4. Using the hands-free phone system (for cellular phones)
Deleting speed dials
STEP 1
Select "Del Spd Dial" using
STEP 2
Press the preset button to which the desired speed dial is
registered after the beep.
The name to be deleted will be heard.
STEP 3
Select "Confirm" using

Limitation of number of digits
A phone number that exceeds 24 digits cannot be registered.
444
CT200h_OM_OM76067E_(EE)
.
.