In , Jim Rech
spake thusly:

so I have to change each formula by hand

There is no way to do what you want. The INDIRECT function is
generally the way to do this but it works only for references
within a workbook, not to other workbooks.

See Laurent Longre's excellent "Morefunc" UDF collection
at http://xcell05.free.fr/ . Among functions in the collection
is INDIRECT.EXT, which, he says, functions the "same as INDIRECT
working also with closed workbooks."

-dman-