Why cant I publish an analysis to replace existing dashboard?

I am an admin in IAM on our AWS account, as well as an admin on QuickSights.

However, when I go to an analysis (that I did not make) and click Share > Publish Dashboard, the resulting modal lets me publish as a new dashboard, but not to replace an existing dashboard.

This means I can’t update existing dashboards, which I need to be able to do. What further permissions am I missing?

You need to be added as a co-owner of the dashboard as well.