Bulk Update of Task Reassignment Privileges

I dont think thats completely possible. AFAIK, there is no OOTB but there is a shared component Reassign With Privileges using which you can partially achieve your scenario. You can change the privileges to "Can only reject the task" so that the Reassign task button doesnt appear. And the good the good this is you can pass task id into this smart service, so you can fetch all the task ids and update them in bulk. Please refer this link https://goo.gl/NZJTcD.
https://goo.gl/NZJTcD

Thanks @sidhantb
The smart service looks good to update process instances. Is there a good way to update the process models in bulk so that we don't have to go through each one manually?

If you go to /designer and edit the field of the Process Model section to show the UUID, you can obtain a list of all the Process Models you need to update and pass all the UUIDs into the Smart Service in bulk.

Oh, good. Thanks Sally, I must have misread the description :)

No worries at all, let us know if you encounter any issues, always happy to help

Hi Sally,

Reassign Privileges smart service is no longer available. Its functionality is moved to Task Management Smart Service. Do you know which smart service will help us to disable all process models/tasks reassignment privileges?

Reassign Task Smart Service may help updating the reassignment privileges of the in-flight tasks, but we want to disable task reassignment privileges globally at environment level.

You can use the Reassign Task Smart Service. You can just reassign it to the same person as it was previous but just update the privileges.