What you describe is a somewhat tortuous approach, but it would be easy enough to identify where the date is located and set a range to that location then write the new date to that range - via a bookmark if you wish, though that isn't really necessary.
As you have not indicated where the date is located in the document or how it is formatted, it is a difficult to advise how to set that range.

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Graham Mayor - MS MVP (Word) (2002-2019)
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