Well, your league Host can disabled the Promotion tho... But I'll prefer those Elite Promotion still, I can just move to better league or start inviting another Elite to my league if it's good (active) enough to promote more Elite in advance... ^^
If promotions could be rejected, the game would be unbalanced, almost no one would advance from tier and many people would abuse staying in lower tiers.
As Sergio says, you can ask your host to deactivate the promotions, or alternatively you can ask him to attract other managers to the elite tier so that there are more people. Although in cases like this the easiest thing is to change to another league.
@Tim
Once you upgrade to Elite, you will remain there. When changing the league the design of the car returns to 0, although it can provide extra points depending on the other teams.
@Gustavo
I think you've been confused, that thread has nothing to do with this.