Replace \r\n with newline in Notepad++

Press CTRL-h and the Replace dialog will open. Type \\r\\n in "Find what" and \r\n in "Replace with". Finally, select search mode Extended (\r, \n, \t, \x..., \0) and click "Replace All".

In the find screen, on the replace tab choose extended search.
In the find text box put \\r\\n, and in the replace text box put \r\n.