Yes, you can. This will remove the report from the timeline at the top of the report.
Simply click on 'Manage Report History' from within the 'Actions' button dropdown.
A page will open showing all of the reports run so far.
Click the 'View Report' button next to the report run that you want to archive and select 'Archive Report'.
A button will appear next to the report run saying 'unarchive' which means that the report has been successfully archived.
The report will now have been removed from the timeline in the main report.
To reinstate the archived report at any time, simply return to the 'Manage Report History' page and click 'unarchive'.