Courier desk

A parcel has an origin, a destination, and a state.

Each scan is a branch and a time. The track the sender sees is those scans.

A bag is a set of parcels on a run. The bag is closed before it leaves.

A missing scan stays missing. The parcel is not marked delivered without a step.

Cash on delivery is a number on the parcel. The rider's return matches it.

The branch sees what arrived and what has not been sent on.

A return to sender is a new leg, not a deleted parcel.

The office can open one tracking number and read the hands it passed through.

A new counter clerk can book a parcel and print the slip from the same row.

The close of the branch is bags out, parcels held, and cash still to deposit.