in this part of the hobbit Gandalf talks to one Bella Donna took son to take him on an adventure but he refuses.
i'm here to take you on an adventure.
no thank you
when Baggins refused Gandalf invited everyone from there team to his house without notice and had a party, Baggins did;t want this.
when the gandalf, and the dwarfs left baggins house there was a note and the signature needed the team with them, when he read the note he changed his mind and ran off to the forest and went to join them, and he did.
i have changed my mind i would like to go on the adventure