curl -X PUT https://api.box.com/2.0/task_assignments/12345 \
     -H 'Authorization: Bearer <ACCESS_TOKEN>" '
     -H 'Content-Type: application/json" '
     -d '{
       "message": "New message",
       "resolution_state": "completed"
     }'

var requestParams = new BoxTaskAssignmentUpdateRequest()
{
    Id = "12345",
    ResolutionState = ResolutionStateType.approved
};
BoxTaskAssignment updatedAssignment = await client.TasksManager.UpdateTaskAssignmentAsync(requestParams);

String assignmentID = "12345";
BoxTaskAssignment taskAssignment = new BoxTaskAssignment(api, assignmentID);
BoxTaskAssignment.Info info = taskAssignment.getInfo();
info.addPendingChange("resolution_state", "approved");
taskAssignment.updateInfo(info);

from boxsdk.object.task_assignment import ResolutionState
updated_task = {'resolution_state': ResolutionState.APPROVED}
updated_assignment = client.task_assignment(assignment_id='12345').update_info(updated_task)
print('Assignment ID is {0} and resolution state is {1}'.format(updated_assignment.id, updated_assignment.resolution_state))

// Complete a task
client.tasks.updateAssignment(
	'12345',
	{
		message: 'Done!',
		resolution_state: client.tasks.resolutionStates.COMPLETE
	})
	.then(assignment => {
		/* assignment -> {
			type: 'task_assignment',
			id: '12345',
			item: 
			{ type: 'file',
				id: '33333',
				sequence_id: '0',
				etag: '0',
				sha1: '7840095ee096ee8297676a138d4e316eabb3ec96',
				name: 'script.js' },
			assigned_to: 
			{ type: 'user',
				id: '22222',
				name: 'Sample Assignee',
				login: 'assignee@exmaple.com' },
			message: 'Done!',
			completed_at: null,
			assigned_at: '2013-05-10T11:43:41-07:00',
			reminded_at: null,
			resolution_state: 'complete',
			assigned_by: 
			{ type: 'user',
				id: '33333',
				name: 'Example User',
				login: 'user@example.com' } }
		*/
	});