True if the workbook is open as a shared list. Read-only Boolean.
Remarks
To save a workbook as a shared list, use the SaveAs method. To switch the workbook from shared mode to exclusive mode, use the ExclusiveAccess method.
Example
This example determines whether the active workbook is open in exclusive mode. If it is, the example saves the workbook as a shared list.
If Not ActiveWorkbook.MultiUserEditing Then
ActiveWorkbook.SaveAs fileName:=ActiveWorkbook.FullName, _
accessMode:=xlShared
End If