How to reactivate old iPhone if returning X?

[pjny]

Hi,

My X is being prepared specifically for my ATT phone number and I suppose will deactivate the old 6s+ when I get it.

I am curious as what is the procedure if you return X in the 14-day period: how do you reactivate your old phone?

 

[cwosigns]

You take the SIM card out of the X and put it back in the 6s Plus.

 

[Spink10]

You take the SIM card out of the X and put it back in the 6s Plus.

Exactly

Another option. When you receive the X before turning it on switch the SIM card with your current SIM.