First of all, assume that you can’t be certain about what is a personal preference or an objection before hearing more. Oftentimes, there is universal wisdom even in what looks like merely personal preference.
That said, don’t get yourself into a position where you are the judge on that. Let the group decide. Also don’t put the objection or the objector on trial. Instead, go through the understand-explore-decide steps: Understand the objection first. Ask the objector to help the group see how their objection shows that the proposal might negatively interfere with the aim of the circle. Then do a round on other people’s thoughts on the proposal and its effectiveness to meet the aim in light of the objection.
Our experience shows that by that time, something will have shifted. Either the wisdom underlying the objection has been found and can now be integrated, or the objector has been listened to and is willing to consent.
For more information, check out our handbook Many Voices One Song sections 3.2.4, 3.5, chapter 3, and read “Strategies for integrating objections”