29 CFR §1206.1

1. (a)In an election among any craft or class where three or more options (including the option for no representation) receive valid votes, if no option receives a majority of the legal votes cast, or in the event of a tie vote, the Board shall authorize a run-off election.
2. (b)In the event a run-off election is authorized by the Board, the two options which received the highest number of votes cast in the first election shall be placed on the run-off ballot. No blank line on which voters may write in the name of any organization, individual, or no representation will be provided on the run-off ballot.
3. (c)Employees who were eligible to vote at the conclusion of the first election shall be eligible to vote in the run-off election except:
   1. (1)Those employees whose employment relationship has terminated; and
   2. (2)Those employees who are no longer employed in the craft or class.