Hello,

I know how to open another workbook in another instance of Excel and
run a macro:

e.g.
Set xlApp = CreateObject("Excel.Application")
Set wbChart = xlApp.Workbooks.Open(filename:=ThisWorkbook.Path &
"\chart.xls")
xlApp.Run "chart.xls!mcrUpdateES", dteClose_15, dblHI_15, dblLO_15,
dblLast

But how do I do this if the workbook is ALREADY OPENED in another
instance of Excel? I think the problem centers on how to identify the
seperate instance of Excel that is already running. i.e. it's easy to
know that "xlApp" refers to the seperate instance if I'm creating that
instance at run-time, but how to refer to the seperate instance if it
was created before run-time.

Any help greatly appreciated.
Ben.