12 CFR §622.57

1. (a)Waiver. Failure to request a hearing pursuant to § 622.56 constitutes a waiver of the opportunity for a hearing and the notice of assessment issued pursuant to § 622.55 will constitute a final and unappealable order.
2. (b)Consent. Any party afforded a hearing who does not appear at the hearing personally or by a duly authorized representative is deemed to have consented to the issuance of an assessment order.