Workbook.ExclusiveAccess Method (Excel)
Assigns the current user exclusive access to the workbook that's open as a shared list.
The ExclusiveAccess method saves any changes you've made to the workbook and requires other users who have the workbook open to save their changes to a different file.
If the specified workbook isn't open as a shared list, this method fails. To determine whether a workbook is open as a shared list, use the MultiUserEditing property.