How do I delete a playlist from iTunes under Sync Music section?

I am using a MAC with iOS 10.13.3 with High Sierra

iMac (27-inch Mid 2011)

Processor 31GHz Intel Core 15

Memory 16 GB

I am trying to remove a 'rogue' playlist that was duplicated from one of my existing playlists, I can remove it from my iPhone 7, but I am unable to remove it from iTunes directly under the "Sync Music" section.

Sorry I did try to find a similar question throughout the forums but nothing came close to what I was asking.

Hopefully someone is able to help please.

Grateful