VBA Code

    ActiveWorkbook.KeepChangeHistory = True 
    ActiveWorkbook.SaveAs _ 
        Filename:= "C:\Personal\Clients\Cust A.xls", _ 
        AccessMode:= xlShared 
    With ActiveWorkbook 
        .HighlightChangesOptions When:=xlAllChanges 
        .ListChangesOnNewSheet = False 
        .HighlightChangesOnScreen = True 
    End With 

    ActiveWorkbook.Save 
    With ActiveWorkbook 
        .HighlightChangesOptions When:=xlHighlightChangesTime.xlAllChanges 
        .ListChangesOnNewSheet = True 
        .HighlightChangesOnScreen = True 
    End With 
    ActiveWorkbook.Save 

ActiveWorkbook.AcceptAllChanges(When,Who,Where) 

When - specifies when all the changes are accepted
Who - Specifies by whom all the changes are accepted ("Everyone")
Where - Specifies where all the changes are accepted

Merged Workbooks

ActiveWorkbook.MergeWorkbook 

Shared Workbooks

There are a number of properties and methods for maintaining, managing and synchronising shared files.
AcceptAllChanges
AutoUpdateFrequency
AutoUpdateSaveChanges
HighlightChangesOnScreen
HighlightChangesOptions
KeepChangesHistory
ListChangesOnNewSheet
ActiveWorkbook.PersonalViewListSettings - True if filter and sort settings for lists are included in the users personal view of a shared workbook
ActiveWorkbook.PersonalViewPrintSettings - True if print settings are included in the users personal view of a shared workbook.

RejectAllChanges

If (ActiveWorkbook.MultiUserEditing = True) Then
End If

ActiveWorkbook.AutoUpdateFrequency = 5 to 1440
This returns or sets the number of minutes between automatic updates to the shared workbook.

ActiveWorkbook.AutoUpdateSaveChanges = True
This returns or sets whether other users will automatically see your changes when the workbook is updated. The default is True.

ActiveWorkbook.ProtectSharing(FileName, _ 
                              Password, _ 
                              WriteResPassword, _ 
                              ReadOnlyRecommended, _ 
                              CreateBackup, _ 
                              SharingPassword, _ 
                              FileFormat) 

FileName -
Password -
WriteResPassword -
ReadOnlyRecommended - True or False indicating whether to display a read only recommendation prompt
CreateBackup - True or False indicating whether to create a backup
SharingPassword - String indicating the password to use
FileFormat - String indicating the file format

UnprotectSharing
This method turns off protection sharing and saves the workbook.
Activeworkbook.UnProtectSharing(sharingpassword)
SharingPassword - String indicating the password to use