I just saw an answer which was flagged as both "low quality" and "not an answer". It was a very short answer but technically correct. Thus I flagged as "invalid flags".
Afterwards I had a look at the question anyhow. And I noticed that there were other answers (given months earlier) which gave the same information. Thus this should have been flagged as "very low quality", I guess.
Is it possible to change a flag? I have not found a way to do so.