49 CFR §209.213

1. (a)Any party aggrieved by a presiding officer's decision may file an appeal with the Administrator. The appeal must be filed within twenty (20) days after service of the presiding officer's decision.
2. (b)Prior to rendering a final determination on an appeal, the Administrator may remand the case for further proceedings before the hearing officer.
3. (c)The filing of an appeal does not stay the effectiveness of a compliance order unless the Administrator expressly so provides.