You can now hand an existing question back to the AI with a prompt. POST /exams/{id}/questions/{questionId}/generate takes a message describing the change you want — "make this harder", "rewrite it for B1 level" — and returns the reworked question in the job result. Set replace to also save it back to the exam.
It's the counterpart to POST /exams/{id}/questions/generate, which writes a brand-new question: same exams:write scope, same asynchronous job result. Handy when you're building questions programmatically and want to iterate on one rather than start it over.