curl --request POST \
  --url https://sandbox.api.portal.io/public/proposals/{ProposalId}/items/costupdate \
  --header 'Accept: <accept>' \
  --header 'Content-Type: application/json' \
  --header 'X-MSS-API-APPID: <api-key>' \
  --header 'X-MSS-API-USERKEY: <api-key>' \
  --header 'X-MSS-CUSTOM-DATE: <api-key>' \
  --header 'X-MSS-SIGNATURE: <api-key>' \
  --data '{}'

import requests

url = "https://sandbox.api.portal.io/public/proposals/{ProposalId}/items/costupdate"

payload = {}
headers = {
    "Accept": "<accept>",
    "X-MSS-API-APPID": "<api-key>",
    "X-MSS-API-USERKEY": "<api-key>",
    "X-MSS-CUSTOM-DATE": "<api-key>",
    "X-MSS-SIGNATURE": "<api-key>",
    "Content-Type": "application/json"
}

response = requests.post(url, json=payload, headers=headers)

print(response.text)

const options = {
  method: 'POST',
  headers: {
    Accept: '<accept>',
    'X-MSS-API-APPID': '<api-key>',
    'X-MSS-API-USERKEY': '<api-key>',
    'X-MSS-CUSTOM-DATE': '<api-key>',
    'X-MSS-SIGNATURE': '<api-key>',
    'Content-Type': 'application/json'
  },
  body: JSON.stringify({})
};

fetch('https://sandbox.api.portal.io/public/proposals/{ProposalId}/items/costupdate', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

{
  "responseStatus": {
    "errorCode": "Unauthorized",
    "message": "Not Authorized. Ensure a valid session cookie or HMAC authentication headers are provided."
  }
}

{
  "responseStatus": {
    "errorCode": "PaymentRequired",
    "message": "The dealer's subscription is inactive or expired. An active subscription is required to use this endpoint."
  }
}

{
  "responseStatus": {
    "errorCode": "Forbidden",
    "message": "You do not have permission for this action."
  }
}

{
  "responseStatus": {
    "errorCode": "NotFound",
    "message": "Proposal not found."
  }
}

{
  "responseStatus": {
    "errorCode": "Conflict",
    "message": "Proposal is in a state that does not allow editing."
  }
}