How to turn off an iphone without using the lock button?

I found an iphone about a week ago. And I just got access to my charger when I came home last night. I found the owner of the phone from the notifications on the phone but she isn't coming to get it until Monday. With that being said the phones lock button is broken and the alarm keeps going off, but I can't get into the phone because there's a lock on it and I can't turn it off because the lock button is broken. What do I do? I just want to sleep lol. But the alarm keeps going off. It shows that the phone is on silent but. It clearly isn't.

Hold on the lock button.

On the top of your iPhone should be a off button if you have a phone case take it off and there should be a off sign on it hold it it should say slide to power off slide it and done

Unfortunately there isn't much that could be done due to that broken lock button. Best you could do is keep it away from you or somewhere to drown out the noise.