HDB do not require two owner, can one owner and one essential occupier.

The essential occupier is free to buy another private property without ABSD after MOP.

https://www.hdb.gov.sg/residential/l...ner-of-holding

If there is more than 1 proposed owner, the proposed owners would need to decide on the manner of holding for the flat, either joint tenancy or tenancy-in-common, upon the change in flat ownership.

https://www.hdb.gov.sg/residential/l...rs/eligibility

However, decoupling the ownership of Housing Development Board flats might not be possible because the Housing Development Board (HDB) revised its regulations on 1 April 2016 to restrict the transfer of flat ownership.

https://singaporelegaladvice.com/law...rs-stamp-duty/

Any doubt check with HDB.

https://www.youtube.com/watch?v=Nv6NWJSG8tc