Matching and Appending Email Addresses from Add People Table to Master People Table

Need to figure a way to do this. I have a table (Add People), which a bunch of rows, and in some (many) of the rows I have email addresses I have a Master People table - with many of the same people in it, how ever, many dont have email address. How do it "match and append" the email addresses from the Add People table where there is a match and the Add People table has emails that the Master table does not have