When a job req creates a new position the date in the "Recruiting Start Date" field becomes the creation date/availability date of the position.  When someone makes a mistake and future dates that field they are unable to take any action on the req until that recruiting start date is reached.  

Typically dates on the job req can be edited by a Recruiter or Recruiting Coordinator in the Edit Job Requisition task. However, they are not able to backdate a requisition prior to the availability date (creation date) of the position.  In cases like this where the recruiting start date needs to be backdated prior to the original creation date, it has to be done by an HCM admin using the correction function on the task where the job req was created.  

To find the job requisition event that needs to be corrected, go to the job requisition page in Workday. View the details page. At the bottom of the page, view the Business Process History and find the most recent Job Requisition Event. That is the event to correct.  Update the recruiting start date field as needed and submit/save the changes.