What are the essential components required for a valid assignment of debt (Huwalah)?

Primary text

A valid assignment of debt requires three parties: the assignor (muhil), the assignee (muhtal), and the assigned party (muhal 'alayh). The consent of the assignor is required without dispute because the debt is his liability, and he is not obligated to specify how it will be discharged. The consent of the assignee and the assigned party is not considered a prerequisite, as will be clarified.