To dynamically update the total cost of a travel reservation as users update each child case component:
B: Configure the Create Case shape to propagate the total cost from each child case to the reservation.
Create a declare expression to update the reservation total when the cost of each component changes.
This approach leverages the use of a declare expression to automatically update the total cost in the parent case whenever any changes occur in the child cases' costs. It ensures that the reservation total remains accurate and reflective of the current costs associated with the flight, hotel, and vehicle rental bookings.