How do I change time display on Watch from 24 to 12 hr.

Hi

To configure your Apple Watch to display 12 hour time format:

On your iPhone, in the Watch app, go to: My Watch (tab) > Clock > turn off 24-Hour Time.

The following steps may help:

Close the Watch app:

• On your iPhone: double-click the Home button, then swipe up on the Watch app preview to close it.

Turn both devices off together, then restart your iPhone first:

• Restart your iPhone, iPad, or iPod touch - Apple Support
• Restart your Apple Watch - Apple Support

You're welcome! 🙂