updateIncidentMutation.gql

mutation updateIncidentMutation($appId: String!, $number: Int!, $state: IncidentStateEnum, $description: String, $notificationFrequency: IncidentNotificationFrequencyEnum, $severity: IncidentSeverityEnum, $assigneeIds: [String!], $notificationThreshold: Int) {
  updateIncident(
    appId: $appId
    number: $number
    state: $state
    description: $description
    notificationFrequency: $notificationFrequency
    notificationThreshold: $notificationThreshold
    severity: $severity
    assigneeIds: $assigneeIds
  ) {
    ... on ExceptionIncident {
      id
      notificationFrequency
      notificationThreshold
      state
      description
      severity
      assignees {
        id
        __typename
      }
      __typename
    }
    ... on PerformanceIncident {
      id
      notificationFrequency
      notificationThreshold
      state
      description
      severity
      assignees {
        id
      }
    }
  }
}

Query variables

{
  "appId": "YOUR-APP-ID",
  "number": INCIDENT-NUMBER,
  "state": "OPEN",
  "notificationFrequency": "FIRST_AFTER_CLOSE"
}