How can I clear the email addresses Outlook suggests?

When I compose a new email, as I type in an email address, Outlook suggests email addresses which I have sent email to previously.

This is a useful feature, but I need to clear the store it is using to suggest these email addresses as many have changed and so it is in fact suggesting out of date email addresses to me.

How can I clear the email addresses Outlook is suggesting (auto-complete) when I type an email address into the To: Field?