Close a file after read/write

How would you set a file read/write to close the file after it is completed with it. I am adding to a CSV file at the end of each day but I would like the ability to edit the files manually if I wish. I receive the message that I can read the contents only.

Not tested but the docs say that if you set the filename using msg.filename it will be closed after every write


so just put a change node before it and set msg.filename