S.D. Codified Laws § 46A-4-56
The board of directors at the time and place mentioned in the notice, or at such other time to which the hearing of the petition may be adjourned, shall hear the petition and all objections to the petition presented in writing by any person. The failure of any person interested in the district or in the matter of the proposed change of its boundaries to show cause in writing is deemed an assent by the person to the change of the boundaries of the district as prayed for in the petition, or to such a change in the boundaries as will include a part of the lands. The filing of the petition with the board is deemed an assent by each petitioner to a change of the boundaries that may include the whole or any portion of the lands described in the petition.
SDCL 46A-4-56