To finance infrastructure projects, the Administration may: make, purchase, and participate in making loans; purchase local obligations issued to finance such projects; and provide any other form of financial assistance other than grants. All transactions under subsection (a) of this section shall be evidenced by instruments containing the terms and conditions necessary to secure payment of all obligations and charges due to the Administration. Subject to an agreement with holders of its bonds, notes, or other obligations, the Administration may consent that a loan, local obligation, commitment, instrument, or agreement that the Administration holds or to which it is a party may be modified as to: interest rate; time of payment of any installment of principal or interest; security; or any other term. In connection with any security that it receives or owns, including a local obligation, the Administration may: sue to protect or enforce its rights under any law or agreement; or acquire or take possession of the security. If the Administration begins such an action, it may: administer the security; pay the principal and interest on any obligation incurred in connection with the security; dispose of the security; and otherwise deal with the security so as to protect the Administration’s interests. The Administration may sell a loan, agreement, local obligation, or other obligation that it holds at public or private sale with or without public bidding.