If you'd like a little more control without having to constantly comment/uncomment the macro, you might add something like this to the macro. Make sure you put it at the top, before any of the other code:
Dim mb As VbMsgBoxResult 'Declare a variable to hold the messagebox result
'Prompt the user:
mb = MsgBox("Would you like to edit this chart?", vbYesNo, "Edit Chart?")
If mb = vbYes Then
Exit Sub 'If user wants to edit the chart, then exit this subroutine
'a response of "No" will allow the sub to continue uninterrupted
End If
Without seeing exactly how the macro is being called, this might require some tweaking, but
it's essentially just a prompt asking whether you want the macro (zoom) to continue, or whether you want it to terminate, allowing you to access the chart object for editing.