Can you write a simple Swagger for an API method that changes the user's last name?

Below is an example of a simple Swagger (OpenAPI 3.0) API method description for changing a user's last name:

openapi: 3.0.0
info:
  title: User API
  version: 1.0.0
paths:
  /users/{userId}/lastname:
    put:
      summary: Change user's last name
      parameters:
        - in: path
          name: userId
          schema:
            type: integer
          required: true
          description: User ID
      requestBody:
        required: true
        content:
          application/json:
            schema:
              type: object
              properties:
                lastName:
                  type: string
                  description: New last name of the user
              required:
                - lastName
      responses:
        '200':
          description: Last name successfully updated
          content:
            application/json:
              schema:
                type: object
                properties:
                  userId:
                    type: integer
                  lastName:
                    type: string
        '400':
          description: Invalid request
        '404':
          description: User not found