1. Install Microsoft Visual Studio Team Foundation Server 2013 Power Tools, then open command line and cd into a location where you have your TFS workspace otherwise TFTP will show error
C:\Windows\System32>tfpt unshelve
Unable to determine the workspace.
  1. Run tfpt unshelve /?
c:\Source\Project\tfpt>unshelve /?
tfpt unshelve - Unshelve into workspace with pending changes

This command has two separate modes of operation:

1. Migrate: allows migration of shelved changes from one branch into another
   by rewriting server paths.

2. Undo: allows changes from an already-unshelved shelveset to be undone,
   cleaning up pending adds, and preserving other existing pending changes in
   the workspace.

Usage: tfpt unshelve /migrate /source:serverpath /target:serverpath
                     [shelvesetname[;username]] [/backup]

       tfpt unshelve /undo shelvesetname[;username] [/batchsize:num]
                     [/recursive] [filespec...]

 shelvesetname          The name of the shelveset to unshelve
 /backup                Creates a backup shelveset
 /migrate               Rewrite the server paths of the shelved items
                        (for example to unshelve into another branch)
 /source:serverpath     Source location for path rewrite (supply with /migrate)
 /target:serverpath     Target location for path rewrite (supply with /migrate)
 /undo                  Undo pending changes from an unshelved shelveset
 /batchsize:num         Set the batch size for server calls (default 500)
  1. The option you need to execute is unshelve /migrate. Specify /source, /target and shelvesetname – that should be enough. You may need to resolve conflicts, in most cases AutoMerge in the pop up dialog will do the trick.