Reply drafts keep threading after recipients are edited

create-shared-mailbox-reply-draft on an automated intro email addresses the draft to the no-reply sender, so check toRecipients before sending. Updating the recipients with update-shared-mailbox-message keeps the conversationId and RE: subject, so the message stays threaded under the original. Replying to the investor's own message in the thread, instead of the platform intro, picks up the right To and Cc automatically. Create and inspect a draft first, then send it: the draft response shows recipients and bodyPreview for checking personalization in a batch.