Can not because you have old number when you are use sim card than whatsapp will assign to current number ( old number ). If you have new sim card than it has another new number than you must say before your friends, family opr beknown than you have new number than you can connect new number under whatsapp :) I have tested my old number from whatsapp and i can not restore because i have new sim card and i haven't access to old number. i must say before my friends, family and beknowns than my family, friends and beknowns reconnect me with new number.. Thanks!