How to close the active task's of a deactivated user

Check this link it has a technical details about how to do, 

community.appian.com/.../handling-assigned-task-for-deactivated-users

1.Build a task report that fetches the details of tasks when you pass the a user or list of users as context (keep the necessary columns in the report for data - Task Id, Context User, Process Instance Id, Date & Time of Assignment/Acceptance, etc.)
2. Build a process model to re-assign/Cancel Process the list of tasks you have identified, to the desired active users using either of the Shared Components - Reassign With Privileges & Task Smart Services Plug-in, based on your need.

Check this link it has a technical details about how to do, 

community.appian.com/.../handling-assigned-task-for-deactivated-users

1.Build a task report that fetches the details of tasks when you pass the a user or list of users as context (keep the necessary columns in the report for data - Task Id, Context User, Process Instance Id, Date & Time of Assignment/Acceptance, etc.)
2. Build a process model to re-assign/Cancel Process the list of tasks you have identified, to the desired active users using either of the Shared Components - Reassign With Privileges & Task Smart Services Plug-in, based on your need.