code: @Override
  	public Response cancelReserve(String corpNum, String receiptNum)
  			throws PopbillException {
  		return cancelReserve(corpNum, receiptNum, null);
  	}
docs: /*
  (non-Javadoc)
  @see com.popbill.api.FaxService#cancelReserve(java.lang.String, java.lang.String)