Finding rows with the same value and replacing one cell with another.

Hello Excel experts! I need your help.

I have two files with loads of different items. All items include article no, description, EAN code, sale price, buy price.
The problem is that one of the files has at many places put the article number and EAN code as the same number. The other file we have
has correct article numbers with EAN codes. What we are trying to do is to compare the two files (or just include one file into another for many rows)
and the search and see if it finds two rows that have the same EAN code value then copy the value from one article number cell (which isn't
the EAN code and replace the faulty one with the new one.

Se image for a clearer picture.

One file contains about 4600 rows and the other 28000 rows and some in those files are the same file but the one with 28000 rows has the article number that we want to use.
Maybe you ask why can't we just use the the bigger file for all our information, well from the smaller file there are other cells with information that needs to remain and together in that file.

Edit: Added a small sample file.