24 CFR §221.252

1. (a)Selling mortgagor. The mortgagee may effect the release of a mortgagor from personal liability on the mortgage note only if it obtains the Commissioner's approval of a substitute mortgagor, as provided by this section.
2. (b)Purchasing mortgagor. The Commissioner may approve a substitute mortgagor with respect to any mortgage insured under subpart A of this part, if the substitute mortgagor is to occupy the dwelling as a principal residence or a secondary residence (as these terms are defined in § 221.20(c)) or is a private nonprofit or public entity as provided in section 221(h) of the National Housing Act.
3. (c)Applicability—current mortgagor. Paragraph (b) of this section applies to the Commissioner's approval of a substitute mortgagor, only if the mortgage executed by the original mortgagor met the conditions of § 203.258(c) of this chapter.
4. (d)Applicability—earlier mortgagor. The occupancy and similar requirements set forth in § 203.258(d) of this chapter apply to mortgages insured under subpart A of this part.
5. (e)Mortgagees approved for participation in the Direct Endorsement program under § 203.3 of this chapter may, subject to limitations established by the Commissioner, themselves approve an appropriate substitute mortgagor under the section and need not obtain further specific approval from the Commissioner.
6. (f)Definition. As used in this section, the term substitute mortgagor includes:
   1. (1)Persons who, upon the release by a mortgagee of a previous mortgagor from personal liability on the mortgage note, assume this liability and agree to pay the mortgage debts and
   2. (2)Persons who purchase without assuming liability on the mortgage note or purchase where no release is given by the mortgagee to the previous mortgagor.