A job posting makes an open hiring requirement visible to applicants. It follows requisition approval and opening. An approved requisition with no posting is ready internally but can't receive a new application through the published-job workflow in Desk Hire.
Read the requisition status and posting flag separately. Withdrawing a posting changes visibility; it doesn't erase the requisition or the applications already received. A filled vacancy shouldn't keep advertising an opening that no longer exists. If headcount changes while a request is still a draft or pending, record the new count before approval. Once the request is approved, treat the requirements as controlled information rather than silently changing them. The exercises include a draft-publication trap so you can distinguish an interface action from a valid business outcome: the app should refuse a posting when its requisition isn't open.