To do this, go to the process page and select Change Responsible in the context menu of the process instance (Fig. 1).
This option is available to the users with permissions to reassign the process instance responsible (by default, the process owner and initiator have these permissions). An administrator can grant the permissions on the access to processes page in the Assign Process Instance Responsiblesection.
Fig. 1. "Change Responsible" option.
In the appeared dialog box (Fig. 2), select a new user responsible for the process instance from the drop-down list and click Set.
Fig. 2. Selection dialog box. Selecting new user responsible for the process instance.