The House of Representatives originally did not pass the 13th Amendment, and on January 1, 1865 it was reconsidered and passed. Evidently, the House first voted that day on whether to reconsider the original vote, and then voted on the amendment itself. Here are the roll calls for the two votes:
The individual votes in the two roll calls are similar, mostly differing in predictable ways.1 The curious exception is John Ganson, who voted "nay" to reconsidering the amendment, but voted "yea" on the amendment itself.
Why did Ganson oppose reconsidering a failed vote when he wanted the amendment to pass? If there is no evidence to come to a conclusion or conjecture in his case, what explanations could there be for anyone voting this way?
1 Schuyler Colfax, the Speaker, is absent on the first roll call (likely due to custom) but did vote on the passing of the amendment, which immediately followed. The other differences are several members who did not vote in the first roll call but participated in the second.