The power and means to terminate the conservatorships is stated in full in the SPSPA Covenants made in 2008:
5.3. Conservatorship. Seller shall not (and Conservator, by its signature below, agrees that it shall not), without the prior written consent of Purchaser, terminate, seek termination of or permit to be terminated the conservatorship of Seller pursuant to Section 1367 of the FHE Act, other than in connection with a receivership pursuant to Section 1367 of the FHE Act.
HERA 2008 originally granted authority and power to the FHFA Director to terminate the conservatorships. This authority and power was legally mitigated by the SPSPAs.