The EXIT statement lets you exit unconditionally from a  SUB  or  FUNCTION
  subprogram, a multi-line DEF, or a statement block.

  Example

  SUB SUBA
  INPUT 'More to do';Answer$
  SUB IF Answer$ = 'NO'
  Loop_1:
      WHILE 1% = 1%
        INPUT 'Amount';Amount
        EXIT Loop_1 IF Amount = 0
      NEXT
  END SUB