Posts and comments are basically the same entity. Opigno API provides the editPost mutation to update the post text. The post can be edited only by the author.
Only a text can be updated. Shared content cannot be changed.
Mutation has a single required incoming argument - data that represents PostEditInput object:
ParameterTypeDescription
postIdIDRequired. ID of the post/comment that should be edited.
textStringRequired. The post body text. Available HTML tags are: <a>, <p>, <br>. Any other tag will be trimmed.
  mutation editPost {
    editPost(data: {
      postId: 175,
      text: "Updated"
    }) {
      response {
        id
        text
      }
      errors
    }
  }
The mutation returns a Post object. Detailed description and the full list of available properties can be found here.