How to clear out Party.BirthDate value?

Hello,

Is there way to set the BirthDate property value to "NULL"?

For example:

{
    "$type": "Asi.Soa.Membership.DataContracts.PersonData, Asi.Contracts",
    "BirthDate": "",
    "PartyId": "101",
    "Id": "101"
}

Sending "" value (as shown from example) in a PUT request does not change the BirthDate property value.
Sending "1753-01-01" value still writes a value however RiSE website won't display the actual date then.

Thank you for any insights there.