So basically I changed my phone recently and I realized I could not change to the new number on whatsapp. It would be troublesome as I have to specially send everyone a text to tell them my new number and they have to add my new number to the groups. Is there any way to change the number? Apparently I have to put the new SIM card into the old phone first, but my new card is a nanosim which is a lot smaller. Besides, my old phone also have problems so I cannot receive messages. So is there any way to change the number? It's ok if I lose the messages, as long as I can stay in the groups. Thanks!