> ## Documentation Index
> Fetch the complete documentation index at: https://docs.orriven.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Cancel a registration

> Releases the seat (and the redemption-code use, if one admitted them). Already cancelled or rejected answers 412.



## OpenAPI

````yaml /api-reference/openapi.json post /v1/events/{eventId}/registrations/{registrationId}/cancel
openapi: 3.1.0
info:
  title: Orriven Developer API
  version: '2026-08-22'
  description: >-
    Workspace-scoped access to events, ticket types, registrations, redemption
    codes, add-ons, bundles, orders (read-only) and check-ins. Authenticate
    every request with `Authorization: Bearer <secret>`; the key's business unit
    is the entire scope, and a resource outside it answers 404, never 403.


    **Versioning** — the API uses date versions (this spec documents
    `2026-08-22`, the current one). A key is pinned to the version current at
    its creation and keeps that behaviour forever; send an `Orriven-Version:
    YYYY-MM-DD` header to serve a single request in another version (unknown
    dates answer 400). Every response echoes the effective version in the
    `Orriven-Version` response header.
servers:
  - url: https://openapi.orriven.com
    description: Production
  - url: http://localhost:3002
    description: Local development
security:
  - bearerAuth: []
paths:
  /v1/events/{eventId}/registrations/{registrationId}/cancel:
    post:
      tags:
        - Registrations
      summary: Cancel a registration
      description: >-
        Releases the seat (and the redemption-code use, if one admitted them).
        Already cancelled or rejected answers 412.
      parameters:
        - schema:
            type: string
          required: true
          name: eventId
          in: path
        - schema:
            type: string
          required: true
          name: registrationId
          in: path
      requestBody:
        required: true
        content:
          application/json:
            schema:
              type: object
              properties:
                reason:
                  type:
                    - string
                    - 'null'
                  maxLength: 2000
      responses:
        '200':
          description: Cancelled.
          content:
            application/json:
              schema:
                type: object
                properties:
                  status:
                    type: string
                required:
                  - status
        '400':
          description: Invalid request body or parameters.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/RpcStatus'
        '401':
          description: >-
            Missing, unknown, revoked or expired API key — all indistinguishable
            on purpose.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/RpcStatus'
        '404':
          description: >-
            The resource does not exist in this key's business unit. A foreign
            id answers the same way.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/RpcStatus'
        '412':
          description: A business rule blocks the change (sold out, currency locked, …).
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/RpcStatus'
        '429':
          description: Rate limit exceeded for this API key.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/RpcStatus'
components:
  schemas:
    RpcStatus:
      type: object
      properties:
        error:
          type: object
          properties:
            code:
              type: integer
              example: 404
            status:
              type: string
              example: NOT_FOUND
            message:
              type: string
              example: Event not found.
            details:
              type: array
              items: {}
          required:
            - code
            - status
            - message
      required:
        - error
  securitySchemes:
    bearerAuth:
      type: http
      scheme: bearer
      description: >-
        The API key's secret (`osk_…`), shown once when the key is created in
        the console.

````