Question

Then he made some notes for the owner, Melanie,who was also the cook.

1.Who should be changed to whom because it is the direct object of the clause.
2.Who should be changed to whom because it would sound more formal
I don't think it should be changed from who to whom just to make it formal but I do think that 2., is the correct answer

Answer 1

Neither answer is correct. The word "who" is the subject of its clause and should never be "whom."