I just changed phones and I am unable to use on my watch. What can I do?

Hi Garybarbour1,

We'll be glad to help you out. From what you've written, it seems like you're referring to setting up Apple Pay on your watch. You can do this by following the steps outlined in Set up Apple Pay - Apple Support

"How to add a debit or credit card to your Apple Watch

1. On your paired iPhone, open the Apple Watch app.
2. In the My Watch tab, tap Wallet & Apple Pay.
3. Tap Add Card.

• Tap Debit or Credit Card to add a new card.
• Tap Previous Card to add a card that you used previously.
  • 

1. Tap Continue.
2. Follow the steps on the screen to add your card.
3. If necessary, verify your information with the bank or card issuer. They might ask you to provide more information or to download an app before approving your card for use with Apple Pay.

"

Following those steps should resolve this for you.

Cheers.