get https://fhir-api.fhirprod.aws.greenwayhealth.com/fhir/R4/TENANT_ID/RelatedPerson
RelatedPersons typically have a personal relationship or non-healthcare-specific professional relationship to the patient. A RelatedPerson resource is primarily used for attribution of information, since RelatedPersons are often a source of information about the patient.
See also:
FHIR RelatedPerson Profile