Pinterest has a deactivate my account function.
After user deactivates his account, he gets an email with Reactivate account link:
Here Reactivate button links to login form with username and password.
But is it OK to link user to login form? I think at that point of time web application shouldn't expect user to know password so it would be better to show a form with just Password and Password Confirmation:
download bmml source – Wireframes created with Balsamiq Mockups
After clicking Unlock my account user would be logged in. I don't see any security vulnerabilities in proposed approach if url to this form contains random unguessable token.