curl --request PATCH \
  --url https://api.example.com/v2/documents/{document_id}/signs/{sign_id}/ \
  --header 'Content-Type: application/json' \
  --data '
{
  "client": 123,
  "method_allowed": [
    16383
  ]
}
'

{
  "id": 123,
  "uuid": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
  "method": 0,
  "signer": {
    "id": 123,
    "name": "<string>",
    "phone": "<string>",
    "email": "jsmith@example.com",
    "type": "company",
    "outer_id": 0
  },
  "status": 0,
  "method_allowed": [
    16383
  ]
}