You would need a macro in Excel to change the data in place.
http://www.mvps.org/dmcritchie/excel/proper.htm#upper

The first macro in that topic will change your existing data in a selection and you
can run it any time. Below that is an Event macro that has to be
customized to which columns you want it to apply to -- it will change
data constants when entered to capitals.
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HTH,
David McRitchie, Microsoft MVP - Excel [site changed Nov. 2001]
My Excel Pages: http://www.mvps.org/dmcritchie/excel/excel.htm
Search Page: http://www.mvps.org/dmcritchie/excel/search.htm

"CT Cameron" <CT wrote ...
How can I change existing text typed in lower case to upper case? In word,
you can select the text and chage case but I can't seem to find the answer in
Excel. I don't want to use the Formula =uppercase(a3) unless there is a way
to change an entire column.