Stuck on the "checking for update" with the little spinning thing

I purchased a new iPhone and I'm attempting to pair my existing watch to the phone, it said an update was needed for the watch. I started the update; however, I did not realize how long it would take and had to "cancel" because I needed to leave. I am trying to restart that process, but am stuck on the "checking for update" with the little spinning thing. I've turned both devices off and back on. I don't know what else to do. Can anyone help?

[Re-Titled by Moderator]