Lexus RX 450h 2010 Owner's Manual, Quick Manual page 54

■ Changing the registered name
STEP 1
: Pressing this switch turns the speech command system on. Say a command
53
after the beep.
Press .
Press and say "Phone book".
Press and say "Change name".
Press and say the desired name.
Press and say "Confirm".
Press and say the new name.
Press and say "Confirm".