iPhone trade

You can trade both phones (if they are models Apple will accept for trade), but only use one specifically for the trade and get a gift card for the 2nd phone, which you can then use as a form of payment towards the new phone.

This is a transaction best done directly in an Apple Store.

See this link for eligibility of phone models for trade and their approximate value (determined after evaluation) --> https://www.apple.com/shop/trade-in?afid=p238%7CrTo88JDV-dc_mtid_1870765e38482_pcrid_78546500880246_pgrid_1256742275320989_&cid=aos-us-kwbi-brand--slid---product-

I don't know of a way to trade two at the same time as you are making a purchase online but you may want to call sales support at 1‑800‑MY‑APPLE to check.

The other option would be to trade-in (or both) one ahead of time for a gift card and then trade the other as part of the purchase. If you decide to do that, see: https://www.apple.com/shop/trade-in

You can trade in one directly for the purchase and a second one for an Apple Store Gift Card which you can then use towards the purchase.

https://www.apple.com/shop/trade-in

LOL.....great minds!!

And one slower mind!

It's a great one none-the-less!