Save As Visual Basic Coding in Excel

I currently have staff use an Excel document with a Submit Button that names and saves the file to our local Shared Drive.  I would like to change the coding so the document uploads to Box.  Any suggestions?  Thanks!

Sub SaveAsDisplay()
        Dim ret_type As Integer
        Dim strmsg As String
        Dim strtitle As String
        strmsg = "Is your form ready for submission?"
        strtitle = "Follow-up Form Submission"
            ret_type = MsgBox(strmsg, vbYesNo + vbQuestion, strtitle)
        Select Case ret_type
        Case 6
            Dim fname As String
            With ActiveWorkbook.Worksheets(1)
            fname = .Range("B3").Value & "_" & .Range("B6") & "_" & Format(.Range("B4").Value, "yyyymmdd") & "_" & .Range("B9").Value & ".xlsm"
            .SaveAs "\\SNDCAFS\Shared\Common\Customer Service\Follow-up Forms\" & fname
            End With
            MsgBox "Your form has been submitted"
            ActiveWorkbook.Close
        Case 7
            MsgBox "Please answer all applicable questions and press Submit again."
        End Select
End Sub