To rename a chart or graph within a Dashboard, simply click on the three dots at the top right of the graph and select 'Configure Chart.' Then type the new name into the 'Chart name' box at the top of the left sidebar and 'Save changes' at the bottom of the sidebar. To rename an entire Dashboard, click on the three dots at the top right of the page and select 'Rename.'   Then type the new name into the box at the top left of the edit screen.