An administrator can invite another user with lower authorization level to edit a specific report before the report has been published.
Click for "Reports" and then "All reports" in the left menu. Unpublished reports are under the "Unpublished" tab. Then click on the title of the report.
Then you end up in this view. Click on the "Participants" tab.
From here you can invite participants to edit the report. Select the people who should be able to edit the report. Then click the "Invite to edit" button.
From here it is also possible to publish the report. Then click the "Publish and invite" button instead.