Updating a link in a file extension dynamically based on a field in that spreadsheet

Hmm. I deduced it was B2 based on your original post. There's nothing in L7. B2 has "07-July" and the path name in G7 has a folder called "07-July" so I'm going with B2.

Here's the solution. Macros must be enabled. Whenever B2 changes, the formula in G7 is updated. If the file in the updated path does not exist, Excel will put up the File Open dialog to allow you to find it.