Unfortunately this cheat doesn’t work on all Sims. It has been tested on 080’s , 070’s and 081’s but still, not on all Sims.
STEPS:
Send M to 799, Wait For Some Seconds
And You’ll Receive A message “Y’ello! You
have Successfully updated Your MOTHER’S NAME and you have received
N400 MTN2MTN Call Usable”..