N.C. Gen. Stat. § 122A-15
The Agency is hereby authorized to provide for the issuance of refunding obligations for the purpose of refunding any obligations then outstanding which shall have been issued under the provisions of this Chapter, including the payment of any redemption premium thereon and any interest accrued or to accrue to the date of redemption of such obligations and, if deemed advisable by the Agency, for any corporate purpose of the Agency. The issuance of such obligations, the maturities and other details thereof, the rights of the holders thereof, and the rights, duties and obligations of the Agency in respect of the same shall be governed by the provisions of this Chapter which relate to the issuance of obligations, insofar as such provisions may be appropriate therefor.
Refunding obligations may be sold or exchanged for outstanding obligations issued under this Chapter and, if sold, the proceeds thereof may be applied, in addition to any other authorized purposes, to the purchase, redemption or payment of such outstanding obligations. Pending the application of the proceeds of any such refunding obligations, with any other available funds, to the payment of the principal, accrued interest and any redemption premium on the obligations being refunded, and, if so provided or permitted in the resolution authorizing the issuance of such refunding obligations or in the trust agreement securing the same, to the payment of any interest on such refunding obligations and any expenses in connection with such refunding, such proceeds may be invested in direct obligations of, or obligations the principal of and the interest on which are unconditionally guaranteed by, the United States of America which shall mature or which shall be subject to redemption by the holders thereof, at the option of such holders, not later than the respective dates when the proceeds, together with the interest accruing thereon, will be required for the purposes intended.
N.C. Gen. Stat. § 122A-15