The Admin will need to reject the page before the page can be made available to others for editing. To do this, the Admin must click on the desired page in either the Ladder
Or the Pages flyout in Pages in the top-level toolbar
Then click on the Reject button
Once the button is pressed, you will get the following popup.
Click Yes to make the page editable again. You will note that the status of the page has moved back to In Progress (indicated with a yellow circle next to the page number at the top of the thumbnail image).