Active Mailings
An active mailing is one that is currently checked out by any user. Click the Active Mailings link in the left-hand navigation to see which mailings are currently active.
Users with the appropriate permissions may check in or steal any mailing from this page by putting a check in the checkbox next to that mailing and clicking the Check In or Steal button. No notification will be sent to the user who had the mailing checked out and they will lose their unsaved changes, so it is a good idea to let that user know before you take a mailing from them.