co-authoring on sharepoint excel file

Hi guys, I'm new here and I've been looking into something for a few days now and nothing seems to work.
We have an excel file on sharepoint and although co-authoring should work it won't merge the updates from multiple users correctly. So I'm trying to think up a code that will allow me to do so.
At this moment I have the following code before anything is saved:

r = Int((5 - 0 + 1) * Rnd)
Application.Wait Now + TimeValue("00:00:" & CStr(r))
If ActiveCell.Value <> "" Then
ActiveCell.Offset(1, 0).Select
GoTo OnResume
Else
ActiveCell.Offset(0, -1).Value = comm
ActiveCell.Value = make
ActiveCell.Offset(0, 1).Value = product
ActiveCell.Offset(0, 2).Value = Date
ActiveCell.Offset(0, 3).Value = enduser
ActiveCell.Offset(0, 4).Value = enduserID
ActiveCell.Offset(0, 5).Value = enduserloc
ActiveCell.Offset(0, 6).Value = quan
ActiveCell.Offset(0, 7).Value = wonum
ActiveCell.Offset(0, 8).Value = reqnum
ActiveCell.Offset(0, 9).Value = getname()
ActiveCell.Offset(0, 10).Value = assigndate
ActiveCell.Offset(0, 11).Value = remark
ThisWorkbook.Save
End If
End If

Anyone has another idea?