List of campaign instances to modify:
Campaign instance payload details:

- id: Campaign instance ID.
- event: The action to apply to the campaign instance.


Allowable values for event are: delete, pause, restart, runnow, end, harddelete.
delete: Transitions the campaign instance to a cancelled state, indicating it is no longer active.
pause: Temporarily halts a running campaign instance, putting it in a paused state.
restart: Resumes a paused campaign instance, continuing its execution.
runnow: Triggers immediate execution of a scheduled campaign instance.
end: Transitions a running campaign to a completion state, before the designated completion date. This is mainly to enforce the campaign closure based actions immediately.
harddelete: Delete the campaign instance immediately from the database.