The plan B is the indoor, or sheltered, version of an outdoor ceremony or reception. You decide it months ahead, not on the morning: where the ceremony moves, whether a marquee goes up, which flowers follow and which stay.
The delicate point is the time of the decision. Your flower designer needs to know the deadline, because setting up twice costs time and money. The contract should say what happens if you change at the last minute. The guide on the wet weather plan explains how to design it; those on the symbolic ceremony and the Dolomites show two cases where you almost always need one.
What to ask: who decides and at what time, which pieces move, and whether the move costs extra.
