Guardian and Power of Attorney are use cases for Related Person, but are not in the provided value set

This is related to FHIR-15841 for a similar issue for Patient.contact. The proposed disposition recommends separating role and relationship as 0..* elements.

We would support this approach, as the MCC project needs to track the relationship to the patient of the person who is performing the role of Power of Attorney

The v3 ValueSet *http://hl7.org/fhir/v3/vs/RoleCode* has the code  POWATT for Power of Attorney and child codes for specific types of Power of Attorney roles (durable POA, healthcare POA, and special POA)