To be able to make changes to the Identity module a box in the Maintenance settings has to be checked. This can be done by clicking on ‘Maintenance’ and unfold the ‘Settings’ menu on the right. The box ‘Has own guidelines’ needs to be checked.
To delete a file you must enter the Identity module and select what you wish to remove (in this case a logo) and press on ‘Edit this page’ on the right.
Select the file you wish to remove. To delete press the delete button, right of the pencil. Before you delete the file you will have to give a confirmation you truly wish to do this action.
This article also has a Youtube video to show how this action can be done.