How do I close or delete a thread on Reddit?

I was wondering if someone could maybe explain how you actually go about locking or deleting a thread on Reddit?
Thanks

If there’s a thread you really want locked down, just hit up the subreddit mods. They’ll usually take care of it for you without much fuss.
You can ask them to scrap a post entirely too, though I get the feeling they only pull the trigger on deletions if things are getting truly out of hand.

Honestly, you shouldn't even have to go through the hassle of messaging the mods just to lock or delete someone else's stuff.

But yeah, there isn't any way for you to do it yourself.