.To change the object, check out the object version if the repository is connected to the Team Foundation Server version control system:
Select the locked object in the object navigator or in the project navigator in the development environment.
NOTE. The icon of the locked object is marked with the corresponding thumbnail. For example, the icon of locked unit looks as .
Execute one of the operations:
Click the 
Check Out button on the object navigator ribbon or in the project menu of the development environment.
Select the Check Out for Edit item in the object's context menu.
After executing the operations the object can be edited and is locked for other developers. The further work is executed with a local copy of files on the hard drive.
If the Automatically Lock Objects for Edit checkbox is selected, the object is automatically checked out and locked on checking out. If the checkbox is deselected, the appropriate locking confirmation is displayed. The objects checked out by one user are available for checking out by other users.
See also:
Developing Application in a Team | Checking In Object Changes