Q. If I deployed Current Branch of Windows 10 and want to move to Long Term Servicing Branch how can I do this?
A. Microsoft documents the legal moves between branches of Windows 10 at https://technet.microsoft.com/en-us/itpro/windows/plan/windows-10-servicing-options. In summary it is not possible to upgrade from Current Branch or Current Branch for Business to the Long Term Servicing Branch. Instead you have to wipe the machine and perform a fresh LTSB installation.