az reservations --help Manage Azure Reservations.

[addaxnasom]

Group
    az reservations : Manage Azure Reservations.
        This command group is in preview. It may be changed/removed in a future release.
Subgroups:
    catalog              : See catalog of available reservations.
    reservation          : Manage reservation entities.
    reservation-order    : Manage reservation order, which is container for reservations.
    reservation-order-id : See reservation order ids that are applied to subscription.