Pop up window to be displayed when using export to XML

Question

I need a pop up window to be displayed(which shows open,save,cancel options) when clicked on "Export to XML" button. The file is being saved in the drive. But I want the user to save the XML file manually in the desired location.

Here is the code which I implemented in button click event.

                    DataSet ods_settle = new DataSet();

                    DateTime sdate = Convert.ToDateTime(txtFromDate.Text);

                    DateTime Enddate = Convert.ToDateTime(txtEndDate.Text);

                    oSAPPGCCSet.StartDate = Convert.ToDateTime(sdate);

                    oSAPPGCCSet.EndDate = Convert.ToDateTime(Enddate.Year + "-" + Enddate.Month + "-" + Enddate.Day);

                    string str_Proc = StoredProcNames.Settlement_usp_fd_GetBillingSettlement;

                    oSAPPGCCSet.ViewSettlement(out ods_settle, str_Proc);

                    grdSettlement.AllowPaging = false;

                    grdSettlement.DataSource = ods_settle;

                    ods_settle.WriteXml("c:\\BillingDate.xml");