What are the conditions for an agent (Wakil) to delegate their agency (Tawkil) to another person?

Primary text

When an agent is permitted to delegate their authority, they must only delegate to a trustworthy person (Amin). This restriction exists because the principal (Muwakkil) has no interest in the appointment of someone untrustworthy. Thus, the permission to delegate is conditioned upon that which secures the principal's benefit and consideration. This is analogous to permission to sell being conditioned upon selling at the fair market price, unless the principal specifically designates the person to whom the agent may delegate; in that case, delegation to the designated person is permissible even if they are not known to be trustworthy, as the principal has waived their right to scrutiny by naming them.