Democrats went through every state in their convention’s roll call vote for the nomination on Tuesday — but Vermont went last (out of alphabetical order) so Bernie Sanders himself could throw the nomination to Hillary Clinton.
After his state’s delegates’ votes were recorded, Sanders spoke up in a choreographed moment. "Madame Chair," he said, "I move that the convention suspend the procedural rules. I move that all votes, all votes cast by delegates, be reflected in the official record. And I move that Hillary Clinton be selected as the nominee of the Democratic Party for president of the United States." With cheers of approval, the convention agreed.
What happened here is that Sanders wanted to make sure all the delegates’ votes for both him and Clinton were properly recorded — but he also wanted to make a gesture of unity, in keeping with his speech Monday night. It also meant that, at long last, he was officially ending his bid for the nomination.