Shared Drafts for Shared Mailbox
This feature lets you share Gmail drafts with your team-mates who are using the same shared mailbox.
To use this, click on the 'Share Draft' button while replying to an email
You’ll be able to save this as a shared draft in the dialog box that opens. The draft is automatically shared with all the users of the same shared mailbox. They will be able to see the shared draft when they open the email.