Hi,
at first: Please use better titles for your threads like "Question about league change". If we read a title like "Question" we don't know what is it about.
These are the penalties you can get if you change the league:
- Deducting 1% of your balance
- Exclusion from the next race
- Car designs reset
- Relegation to the next lower tier
- No penalties
If I remember correctly it doesn't matter if you leave and then go back to the previous one.