curl --request PUT \
  --url https://cloud.memsource.com/web/api2/v1/buyers/{buyerUid} \
  --header 'Content-Type: application/json' \
  --data '
{
  "defaultProjectOwner": {
    "id": "<string>"
  }
}
'

{
  "uid": "<string>",
  "defaultProjectOwner": {
    "firstName": "<string>",
    "lastName": "<string>",
    "userName": "<string>",
    "email": "<string>",
    "role": "SYS_ADMIN",
    "id": "<string>",
    "uid": "<string>"
  },
  "vendorOrganization": {
    "id": "<string>",
    "uid": "<string>",
    "name": "<string>"
  }
}