Sometimes you'll need to reopen a message, that might be because you accidentally closed it (it happens!) or because you want to add some new information. It's easy to reopen a new message, just follow the steps below:
Head to 'Message search'
Search for the message you need to reopen. Hint: narrowing down the date will help you if you don't have any other identifying details to hand!
Click into the message you need to reopen
Click the 'Reopen' button at the top right of the screen