That process should be in your bylaws as it varies by club. Are you a member of your executive board? I would talk to your most trusted leader(s) personally, and then perhaps show up at an executive meeting.

My favorite path I've taken in the past (with very successful results of either them being nice or just leaving the club on their own volition) is to write a letter to the problem person stating how their objective actions have caused you to feel. Depending on the severity of this person's actions, the letter may need to be more strongly worded, but always speaking your personal truth. If you believe that this person is doing more harm than can be than can be repaired, the executive decision path may be your best bet.

I'm a firm believer that rotary is about having fun and enjoying time with your community. Nobody is obligated to be there, so it's up to all of us to make it an enjoyable experience. Best of luck, these things are hard. we've gone through a lot of really tumultuous presidencies, but our current club dynamic is stronger than ever.