Hi Bob,
Thank you for your response.
To illustrate what I want, I've made two files:
https://www.dropbox.com/sh/3klscgv1w...2RqqLt1Ga?dl=0
The "backend" is the input excel-file. (which I called input.xlsx in my first post)
The "frontend" is the interface for the end-user. (which I called lookup.xlsm in my first post)
I would like to update the data (in the backend file, table starts at cell A1) via the frontend file (where you can filter the data for looking up the right record).
I've added some explanations in the files themselves.
Hopefully, my explanation is clear enough.