The default in Covidence is that 2 reviewers must go through each stage of the review process. If you are completing an individual review, you must customize these settings before you begin. Otherwise, you will not be able to move forward because Covidence will think there's another reviewer waiting to complete their part of the work.
To make changes, click Settings and then Review Settings. Scroll to the bottom.
Here you will see three drop down prompts and menus:
As you can see, the default is for 2 reviewers at each stage. Click the drop down menu and select "1" for each of these three categories. Make sure to click the blue Save button at the bottom once you're finished.
