Int 2F Fn 1208  U - DOS 3+ Internal - Decrement Sft Reference Count        [D]

   AX = 1208h
   ES:DI -> SFT

Return: AX = original value of reference count

Notes: if the reference count was 1, it is set to FFFFh (since 0 indicates
     that the SFT is not in use).  It is the caller's responsibility to
     set the reference count to zero after cleaning up.
   used by network redirectors such as MSCDEX

See Also: AX=1106h