I know it’s possible to convert a normal post into a whisper (and vice versa), but can a normal post be converted into a post action?
AI-generated summary
hello-smile6 asked if it was possible to convert a normal post into a post action using the API, like how posts can be converted into whispers. maiki suggested trying the same method as the whisper-toggling API call, but specifying the post action type instead. hello-smile6 confirmed that sending a PUT request to the /posts/{post_id}/post_type endpoint with a body of post_type=3 does successfully convert a post into a post action.
Try the same method as the whisper-toggling call, but with the post action type. 
It worked! It seems like sending a PUT request to $baseUrl/posts/$post_id/post_type with a body of post_type=3 converts a post into a post action.