To verify whatapp by interchanging the SIM cards

Here we are going to see how whatsapp works when two registered mobile numbers(SIMS) are interchanged.
For this you need to have two mobiles registered with their own mobile numbers.
Now to verify the above scenario,follow the procedure:
But you need to connect to a WiFi/mobile data.

1. Switch OFF both the mobiles A & B.
2. Remove both the registered SIM cards from mobile A and B.
3. Insert the SIM card of mobile B in mobile A.
4. Insert the SIM card of mobile A in mobile B.
5. Turn ON mobile A.
6. Turn ON mobile B.
7. Send a message from any other mobile to mobile A removed SIM number.
8. Message will come to mobile A only, even though it is using mobile B SIM.

By this it is observed that whatsapp will work even though the SIM card is changed/removed.
But this scenario will work untill we change the number in “change number” option in settings or if we uninstall and reinstall the application.