Mo. Rev. Stat. § 115.181: Canvass, how conducted.

1. In its discretion, the election authority may order all or any part of a canvass to be made house-to-house, through the United States Postal Service, or by both methods.

2. At the discretion of the election authority, the canvass may be made by including only those voters who did not vote at the last general election and those voters who registered since the last general election.