Select into OUTFILE -- how do you append or delete

I have a query that will run and create the file right, however now I need to make some edits. First I need a version that will append to an existing file.... and another that will delete the file if it exists.  

so say I this was the query I was using what would it look like in the above situations...

SELECT insertstatement INTO OUTFILE 'C:\\MW2MP\\conversion.sql' from sqlinserts;