curl --request PATCH \
  --url https://channels-service-alpha.fourvenues.com/bookings/{bookingId}/observations \
  --header 'Content-Type: application/json' \
  --header 'X-Api-Key: <api-key>' \
  --data '
{
  "observations_referral": "This client is a VIP. Please give him a good table."
}
'

{
  "data": {
    "_id": "5f8e1b9b9d9e4b0017b3b3a0",
    "organization_id": "5f8e1b9b9d9e4b0017b3b3a0",
    "channel_id": "5f8e1b9b9d9e4b0017b3b3a0",
    "referral_id": "5f8e1b9b9d9e4b0017b3b3a0",
    "status": "accepted",
    "quantity": 10,
    "full_name": "John Doe",
    "email": "john.doe@example.com",
    "phone": "1234567890",
    "deposit": 100,
    "fee_type": "percentage",
    "fee_quantity": 7,
    "qr_code": "ABCDE12345",
    "activation_code": "ABCDEFGH12345678",
    "observations_referral": "This is a referral",
    "observations_client": "Please give me a good table",
    "payment_id": "pay_1234567890",
    "marketing_consent": true,
    "billing_info": {
      "customer_type": "individual",
      "customer_name": "John Doe",
      "document_type": "dni",
      "document_number": "12345678Z",
      "address": "123 Main St",
      "city": "Barcelona",
      "postal_code": "08001",
      "country": "ES"
    }
  },
  "success": true
}