You can rename a collection on the Mapping screen.
You cannot rename a collection to a name that is already in use, nor can you
leave the Name text box blank, as both actions result in an
error.
To select a collection on the Mapping screen:
Click on a collection in the MongoDB diagram, or
Click on a collection listed under the MongoDB header on the
Schema Model pane.
On the Mappings pane, click the Name text box and enter
the new name.
Click anywhere outside of the text box to save the changes. The name is updated on
the MongoDB diagram and the Schema Model pane.