Can I use different Apple ID's for my iPhone and Apple Watch?

It's not entirely clear what you're asking. If you want to have the watch set up to a different Apple ID than your phone, you can but there are limits to some features. And the watch has to be one with cellular.

Set up Apple Watch for a family member - Apple Support

If I recall you are asking to re-pair your Apple Watch to the same Apple ID as your iPhone? Refer to this video:

Pair your Apple Watch with your iPhone ⇢ If you can't pair an Apple Watch with your iPhone - Apple Support