I have served on the arbitration panel as the plaintiff's arbitrator. This was a three-member panel and one member was the neutral. Subsequently, the plaintiff has come to me to represent them on issues involving this matter. Can I do so?

The normal answer for most arbitrators or mediators would be no. But there is an exception under Rule of Professional Conduct 1.12 involving a partisan arbitrator. Under Rule 1.12(d), a partisan arbitrator can subsequently represent the party: