[Jonathan Visser]

Like Pasha said: before 5-min period, you can click "quit" button to unregister from race with no penalty whatsoever, it's fine.
After 5-minute window closes, you can no longer unregister. If there are less than 6 people REGISTERED at this point, you can just not join the race session and it won't matter as the race is not considered "official." No championship or rating points are awarded, or taken away from you, nor will you get any penalties.
Or you can go race a practise session with other guys if you want (if anyone will show up).
In the case you are registered after 5-min period and the race goes official with min 6 people registred, you should join the session and drive minimum of 3 RACE laps to not get DNF that gives you negative impact on your rating. If you skip the official min 6 driver race altogether, you won't get banned but will get negative impact on your rating.  (I'm not sure how many races you can skip until you get a suspension penalty?) Practice or quali laps won't matter, you want 3 race laps. You can even join race session after the start, start from grid and go do your 3 laps, watching out for blue flags all the time of course. This stuff actually happens quite often as people have unexpected tech problems that may cause them missing out on quali or even the race start.

The rules are there to get people actually go in the races they register on. So always try to go in the race you register on, or quit before the 5-min limit, but no need to panic if something happens that prevents your participation, you just get a small negative rating impact. People have surprise real life things happening  and technical issues sometimes, it's fine.

Side note here: race still goes official as long as there are min 6 people registered by the 5-min limit, even if not all of them join the session. You will get your championship points if you race.

Thank you so much man. I will leave the next time and not wast 30 min of my day. thanks