42 CFR §422.668

1. (a)A hearing officer may not conduct a hearing in a case in which he or she is prejudiced or partial to any party or has any interest in the matter pending for decision.
2. (b)A party to the hearing who objects to the designated hearing officer must notify that officer in writing at the earliest opportunity.
3. (c)The hearing officer must consider the objections, and may, at his or her discretion, either proceed with the hearing or withdraw.
   1. (1)If the hearing officer withdraws, CMS designates another hearing officer to conduct the hearing.
   2. (2)If the hearing officer does not withdraw, the objecting party may, after the hearing, present objections and request that the officer's decision be revised or a new hearing be held before another hearing officer. The objections must be submitted in writing to CMS.