Emergency Action: Stop Publishing
Account Admins can convert all posts scheduled for the next 24 hours to draft posts. This is useful when all publishing needs to be halted in the event of a crisis or other unforeseen circumstance.
Because this action cannot be reversed in bulk, you must input a security phrase before you can convert the posts. After your scheduled posts convert to draft posts, you can reschedule each post individually after any necessary edits, or you can delete them.
This action only affects posts that are already scheduled. If you create and schedule a new post within 24 hours after converting your other posts to drafts, that new post will still go live.

The following scheduled posts are not affected by this action:
Posts that are Scheduled on Facebook (see Scheduling Options for more information).
Scheduled posts that are still in the approval flow:
Even if you stop publishing, these posts will not be automatically changed or canceled by the Stop Publishing action. This means that if a post is approved after you perform the Stop Publishing action, and that post is scheduled to post within the 24-hour period of time in which you wanted to halt all publishing, that post will publish.
However, if a post has already been approved but has not yet been published, and it is scheduled to publish within the next 24 hours, then Stop Publishing changes the status of that post to Draft.
Steps:
Open Publisher → Scheduled.
You can also open Publisher → Calendar and click the ellipsis (…) menu.
Click Stop Publishing.
A confirmation window opens that shows the approximate number of posts that will be converted to drafts.Click the checkbox to confirm you understand the action is irreversible in bulk.
The text field for the security phrase prompt appears in the confirmation window.Enter the security phrase into the text field.
Click Convert (###) posts to drafts.
All posts that were scheduled to publish 24 hours from the time of clicking the button convert to drafts.