I have two similar workbooks. In both the original and the modified, the
data in columns A-D is essentially the same, although formatting,
columnwidth is different.

In the modified, I have new data out in columns E-F which I need to copy
into the original.

This is not a straightforward copy because of additional blank rows between
data and additional data in cols A-D in the modified book.

Can I read a line in the original, find that line in the modified (if it
exists) and then copy any additional data from the modified back to the
original?

Regards and thanks.