Can't port number till 10/22, can I use my ATT sim in new Verizon iPhone 7?

[nottooshabby]

I'm switching from ATT to Verizon. I went ahead and ordered my iPhone 7 from Verizon to take advatange of the trade-in deal. My JB7 is arriving earlier than expected. If I activate the iPhone 7 on verizon to start my service, can I then change the sim card to my AT&T time card till 10/22(when contract is up), then start the porting process with Verizon? That way I can still use my new iPHone 7 and send my iPhone 6 in as the trade.

Thanks

 

[Bigserver1]

You should be able to, yes. Verizon phones are unlocked, so your ATT sim should work just fine.