Facilitation Neutrality
Separating the role of running a discussion from the role of advocating within it, because one person cannot do both credibly.
A technical discussion led by someone with a stake in the outcome is not a discussion, and participants know it. The facilitator's job is process; the participant's job is content, and holding both means the process will be shaped, consciously or not, toward a preferred conclusion.
Where the architect must contribute substantively, the answer is to name the switch explicitly — "I'm going to take my facilitator hat off for a moment" — or to hand facilitation to someone else for the session. Both are better than pretending neutrality nobody believes.
What a facilitator actually does: states the objective and what a decision would look like; ensures the quiet people are heard, since the loudest view is not usually the best-informed one; surfaces disagreement rather than smoothing it, because unspoken objections do not disappear; times the discussion and calls the point at which more debate will not help; and records the decision, the reasoning, the objections and the owners.
Two techniques that improve technical discussions markedly: independent written positions before discussion, which prevents anchoring on whoever speaks first and surfaces the true spread of opinion; and explicitly separating divergence from convergence, so that option generation is not shut down by premature evaluation.