LG MX8550 Service Manual page 18

You can edit the NAM1 Phone Number (MDN).
Press softkey "OK" (Message key) to edit more NAM1 items.
Press softkey "Exit" (Contacts) to edit previous NAM1 items.
5) NAM1 Phone Number (MIN)
You can edit the NAM1 Phone Number (MIN).
Press softkey "OK" (Message key) to edit more NAM1 items.
Press softkey "Back" (Contacts) to edit previous NAM1 items.
6) NAM1 Home SID
You can edit the NAM1 Home SID.
Press softkey "OK" (Message key) to edit more NAM1 items.
Press softkey "Back" (Contacts) to edit previous NAM1 items.