The CLOSE statement ends processing of reels (or units) and files.  It
  can also perform rewind, lock, and removal operations.

  Format -

         {           [ { REEL } [ FOR REMOVAL    ] ] }
   CLOSE { file-name [ { UNIT } [ WITH NO REWIND ] ] } ...
         {           [ WITH { NO REWIND }          ] }
         {           [      { LOCK      }          ] }

1 - file-name

  is the name of a file described in the Data Division.  It cannot be a
  sort or merge file.