One instance where you may have to request read and write permissions back-to-back is the first time that you're associating an email-based account with a person's Facebook account. This is usually done when someone wants to share a story on their Facebook Timeline.ne instance where you may have to request read and write permissions back-to-back is the first time that you're associating an email-based account with a person's Facebook account. This is usually done when someone wants to share a story on their Facebook Timeline.