25 C.F.R. § 519.3 – Methods of service.

(a) The Chairman shall serve any official determination, order, or notice of violation by:
1. (1) Delivering a copy to a designated agent;
2. (2) Delivering a copy to the person who is the subject of the official determination, order, or notice of violation;
3. (3) Delivering a copy to the individual who, after reasonable inquiry, appears to be in charge of the gaming operation that is the subject of the official determination, order, or notice of violation;
4. (4) Mailing to the person who is the subject of the official determination, order, or notice of violation or to his or her designated agent at the last known address. Service by mail is complete upon mailing; or
5. (5) Transmitting a facsimile to the person who is the subject of the official determination, order, or notice of violation or to his or her designated agent at the last known facsimile number. Service by facsimile is complete upon transmission.
(b) Delivery of a copy means: Handing it to the person or designated agent (or attorney for either); leaving a copy at the person's, agent's or attorney's office with a clerk or other person in charge thereof; if there is no one in charge, leaving it in a conspicuous place therein; or, if the office is closed or the person to be served has no office, leaving it at the person's dwelling house or usual place of abode with some person of suitable age and discretion then residing therein.
(c) Service shall not be deemed incomplete because of refusal to accept.