When a destination is deleted/hidden, option to reassign carpools to that destination to other destinations

[flynnwastaken]

An dropdown of other destinations, to assign any carpools going to a destination you are about to delete/hide to that destination instead

Why:
If a campaign sets up a location as a destination for a single event/weekend/etc, and people sign up to go there at later dates, the campaign still wants people to come, but probably to a different office or staging location. This feature would make it so the carpool would not be lost, and the volunteers would not have to recreate it and re-find eachother