Client names in 2 different formats - how to match them?

Hi! Hope you are all safe.

Question: I have a list of clients in our accounting system, they are all "Last Name, First name" [example: Smith, John]; or "Last Name, First Name and Spouse Name" [example" Smith, John and Jane".

I received a report with more than 1000 entries that I need to enter in our accounting system, I'm able to upload if I can map it but the names are in a few different formats. I cannot upload it like that or the software will think they are new clients.

Some names are as above, but other start with first name, like "First Name Last Name" [example: John Smith], or "First Name and Spouse name Last Name" [example: John and Jane Smith".

Is there a formula that can compare and match the names even if they aren't written in the same way, maybe compare last names only? Then, if it's a match, I would like the "last name, first name" to be default one.

Let me know excel gurus!!! Thanks!!!!

Post a small Excel sheet (not a picture) showing realistic & representative sample data WITHOUT confidential information (10-20 rows, not thousands...) and some manually calculated results. Just before posting, scroll down to GO ADVANCED, click, and then scroll down to MANAGE ATTACHMENTS and click again. Now follow the instructions at the top of that screen.

Grazie mille!

Here is a sample. I hope it makes sense.