I have a macro in Outlook VBA to grab data from an open Excel workbook (\"Workbook1\").
I reference the workbook as follows:
Dim objApp As Excel.App
If you want to set the objApp to a particular instance of Excel,
you can do so using the name of an open workbook in that instance:
Dim objApp As Excel.Application
Dim objWbk As Excel.Workbook
Dim wB As Excel.Workbook
Set objWbk = GetObject("Workbook1.xlsx")
Set objApp = objWb.Application
Set wB = objApp.Workbooks("Workbook1.xlsx")