One last step...

• Return to the Channel where the original of your duplicate is located.
• Click on the "Add to" icon on the bottom right of the duplicate Guide thumbnail.
• At the bottom of the window that opens, you will see an option to "remove from current channel". Click on this and the Guide duplicate will disappear from that Channel.

Your new copy now lives in its own Channel and you can edit freely without changing the original. Once you're ready, click Publish and release it to your colleagues, friends and the Guides universe!