How to get there: Click All Posts in the sidebar, open the duplicate post, click the More (⋯) menu, then choose Merge.
Merging takes a duplicate post and folds it into the canonical one. All the engagement on the duplicate (votes, followers, comments) moves over to the target, and anyone visiting the old URL is redirected.
The Merge screen shows the post you are merging from at the top and a search box for the target post. Search by title, pick the target, and confirm.
Before merging, consider marking the source as Duplicate of the target using the Linked Posts panel. It gives you a paper trail and a chance to think twice. See Link posts and inline post mentions.
You can also ask Nova to find and merge duplicates for you. Prompts like "are there duplicates of post ABC123?" surface the ranked candidates; Nova will only run the merge after you confirm with an explicit "yes" or "merge them", so the same irreversibility guard applies.
Merging is not reversible. Once you confirm, the source post is redirected and its votes, followers, and comments belong to the target. Review the target post carefully before confirming.
If you merged the wrong way around (the smaller post was actually the canonical one), the cleanest fix is to leave the merge in place and rename the target. Splitting back out via Split posts is possible but does not restore the original comment thread.