Depends what the revisions are. You may be able to do it with Edit>Replace,
but it is probably easier to go back to the main document, revise it and
then re-execute the merge.

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Hope this helps,
Doug Robbins - Word MVP
> I've already done the mail merge and I needed to revise
> the letter after this was done. Is there a way to revise
> the already merged document or do I need to just do a new
> mail merge?