Duplicate information across multiple spreadsheets that are amalgamated?

I have what is (for me, at least) a somewhat complicated Excel Duplicates issue and am hoping that you can help!

A window has opened which allows individuals to login to an online account and provide us with information that we will use, when this window closes, to transfer some assets. There is a plethora of information on these spreadsheets, including names, addresses, types of asset, unique identifying numbers etc (it goes on and on). Each day this information gets pulled into a spreadsheet and sent to me. I have to split it down depending on the destination of the assets.

Here's the problem. The individuals can change their information at any time, so from one day to the next they can go on and change things such as the destination of the shares and the reference number. Sometimes the information won't change at all and sometimes entirely new people will appear on the daily spreadsheet.

At the end of the week, I have to combine these daily spreadsheets into one and eliminate any duplicates and - where changes have been made - utilise only the most recent data.

Below I have attached two spreadsheets in a very basic format to try and demonstrate what it is I am seeing. They are incredibly condensed compared to the real thing. If you feel that would need to see the real thing, please let me know and I will spend sometime making the spreadsheet anonymous and removing any sensitive information.

If you have any questions then please let me know and I will do my very best to answer.

Thank you for your help.

Day 1.xlsxDay 2.xlsx

Any help on this one?