have a apple watch thats icloud locked how can i pair to new phone?

Hi

You are describing Activation Lock, which prevents unauthorised use of Apple Watch if it is lost or stolen.

If the watch is locked to your own account, but you are having issues with your credentials:

It may help to follow the instructions here:

If you still need assistance, contact Apple Support or make a Genius Bar reservation, taking along your Apple Watch and your original proof of purchase for it:

• Contact - Official Apple Support
• https://twitter.com/applesupport
• http://www.apple.com/retail/geniusbar/

If the Apple Watch is pre-owned and locked to the previous owner's account:

• You will need the previous owner (who may not be the seller) to either enter their Apple ID and password on your iPhone or to turn the feature off via https://www.icloud.com/ by signing in with their Apple ID > Settings > My Devices > Click on Apple Watch > Click on the "X" > click on Remove.
• If you cannot arrange for the previous owner to do this, you should return the watch for a refund.
• You will not otherwise be able to use the watch. There is no way around this security feature.

More information:

About Activation Lock on your Apple Watch - Apple Support

That depends on whether it's locked to your account or someone else's... If it's locked to someone else's account, you can't. Not until they remove the lock.