Which role is accountable for the operational management of a process?

A process practitioner executes defined process activities and tasks but holds no accountability for the overall operational management of the process.

In ITIL, the process manager is explicitly defined as the role accountable for the operational management of a process, including planning and coordinating all process activities, ensuring process objectives and KPIs are met, and managing the process team. This distinguishes the role from the process owner, who is accountable for the process design and strategic fitness.

A service manager has end-to-end accountability for one or more IT services as a whole, not operational accountability for a specific process.

Change manager is a specific instance of a process manager role scoped to the change management process - it is not a generic role that answers this question about process operational accountability.