The Alliance Members are classified into 6 Ranks: R0, R1, R2, R3, R4, and R5. Different Ranks have different privileges. You can go to Alliance - Members, and then tap the “!” button in the upper right corner to check the permission details.
1) Only the Alliance Leader or a Member whose Rank is at least 2 levels higher than you has the right to edit your Alliance Rank. If you meet one of the above 2 conditions, you can promote or demote other Member(s) as well.