An independent shop's phone rings at the service counter, and the person at the counter is usually under a hood. A caller with a check-engine light books with the shop that answers. MairyAI answers on your own number, states that the caller is speaking with an AI assistant, takes the vehicle and the symptom, and books the drop-off into the calendar you already use.
Status calls from customers whose cars are in the bay get an answer from what you have provided or a message to the advisor. Every call is written up with the vehicle, the problem and the appointment, and the customer gets an email confirmation in your words.