Whenever you save a version of your dashboard, a copy of that version is saved so that previous versions of your dashboard are never lost. You can view previous versions by clicking on the View Dashboard History option.

WIthin the dashboard version table, you can click [restore] to restore any previous version.

Dashboard History Dashboard History Listing

If you select [diff] you can see what changed between versions:

Dashboard History Diff

Alternatively the View Raw JSON option allows you to edit or copy-paste raw JSON between Pulse dashboards or instances.

Dashboard Raw Json