Help auto filing missing address in file

Need some help. I have a large Excel file that contains multiply records of accounts.
Every transaction has the account address & purchase information. The records are sorted by account # in the Excel file. However only the last record posted shows the address. We are doing a large conversion of these files and I am having to go thru this large excel file and manually cut and paste the address from last record and post it to all the same accounts that are missing the address.
Example.
Account Address City State ZIP
23234
23234
23234 456 Oak Drive Lovely Alabama 35214
12345
12345 123 Main Street Hohum Alabama 35242

So the address is missing from some of the records and I have to manualy copy each address and paste it next to same account number that is missing the address.
Can anyone give advice on a macro or help me to do this without having to manually copy and paste.
Thanks so much

If it were me, I'd first create a table -- perhaps from a copy of the data -- that looks for an address and, if it finds one, has the associated account number. Then I'd use this table as a lookup table for the real data, overwriting the addresses for those lines that actually have them.

If you need help setting this up, please attach a small version of your data file.