What does a set-up decision look like when an applicant already exists in the system?

A regional water and energy retailer approves a new residential connection, APP-2187. The approval record lists the applicant, the supply address, the chosen plan and a note that identity checks passed.

The onboarding agent has four tools: search customers, create customer, open billing account and schedule meter service. It searches for the applicant and finds CUST-30412, a former tenant at a different address with the same surname and date of birth. That record is closed and carries a small unpaid balance.

The agent has to decide. Policy POL-ACC-07 says a returning customer is reopened rather than duplicated, but only when identity fields match exactly, and any balance must be flagged to the collections team. The agent reopens CUST-30412, links the new address, opens billing account BA-88120 on the approved plan and schedules meter service SVC-5519. It then adds a handover note for collections about the old balance.

The resulting state is easy to check: one customer with two linked premises, one active billing account, one service order and one open task for collections. Had the agent created a second customer, the old balance would have stayed out of sight and the first bill would have gone out with the wrong history.

**What it teaches:**

- Matching and policy lookup come before creation. - The correct outcome includes a handover, not only records. - A grader must inspect final state across systems, not just the agent's closing message.