Do Azure Reservations automatically renew?
Reservations do not automatically renew, but customers are sent notifications about upcoming Reservation expiration, and can choose to opt in to automatically renew the Reservation at any time. This will purchase a new Reservation at the relevant time rather than extending the term of an existing one. If a Reservation is not set to automatically renew then there is no interruption to the workload, it just starts being charged at regular metered prices. As soon as another Reservation is purchased it is automatically applied to the relevant workload. Page 334, BOK21