You can unsubscribe the membership by doing this:

- Click ‘Settings’ in the topbar (under your name/username)

- Scroll down to the bottom of settings and click on "My Premium"

- Click the ‘Unsubscribe Premium' button to unsubscribe

When you have unsubscribed the membership, you receive an e-mail confirming the membership has been unsubscribed.

Even though you unsubscribe the membership before it expires, you can still use it the for the remaining days as you paid for.