this kind of situation is always a challenge.
You sure you can't go back to the source data  and make sure it gets
entered consistently? Why is there some system that has the data being
entered inconsistently? You really sure you can't do anything about
that?

Next, is there some way an account number  is already assigned to each of
these records? Then you wouldn't have to worry about spelling
inconsistencies.

I can't see any way that the final word in a situation like this could
rest anywhere than on a human. Some person has to sit there and make a
decision about which ones are matches or not.

Of course, the computer can help -- maybe you create an algorithm that
says if the first bunch of characters match, and it's 75% of the total
string length, then it's a match. So 12345678 and 12345699 would match
because the first 6 of 8 chars match (75%). Something like that...?

. You need to catch your problem  at the source,
and that is the user input. By creating  a master  list, that can be
updated and edited by the user, you will be able to organize your data
later.

Personally, I am a believer in using MS-Access with MS-Excel. By placing
this data  into a single repository for user entry, and then exporting it
to Excel for reporting. Either way, your goal is to control the user
input.

Since the different names  reference the same account, we can surmise
that there is data that the two share. By creating a master list, and a
user input form, you can control how the new names are entered. The user
will have to select the account the names are associated with, and
viola! You have a key to link all your data.