The PERFORM statement executes one or more procedures.  It returns
  control to the end of the PERFORM statement when procedure execution
  ends.

  Format 3 -

   PERFORM [first-proc [ { THRU    } end-proc ]] [ WITH TEST { BEFORE } ]
           [           [ { THROUGH }          ]] [           { AFTER  } ]

       UNTIL cond

    [ stment  END-PERFORM ]