Yes, you can. The code  is accessible in a collection, and you can certainly
change it.

However, can I suggest a possibly easier way ...

- Create a new workbook
- Copy the summary  sheet to it
- Delete any other sheets in it (i.e. the default "Sheet1", "Sheet2", etc)
- Save and close this workbook  as your summary.

This is all done in just a few lines of quite straightforward code. Manipulating
the vba  code object is much less straightforward.

An alternative is to leave the code in the summary workbook, but have it check
for the absence of a key worksheet  and just not do anything if the sheet isn't
there.

You may want to think about pastespecial'ing just the values as well.
That makes it a "real" summary... sort of.

If the summary  sheet contains formulae
that reference other sheets, it is important that you do a paste values to stop
the summary sheet having links back to the non-summary sheet.

You could do a copy of the sheet first, so that the formatting is correct, then
select the entire sheet and copy/paste-values of itself to itself.