Is PHP capable of doing some things on its own?

For example, when user buy "ticket" it is valid for 10 days.
Now if he bought it at 2006-09-05, it is valid until 2006-09-15(this date included).

Now we are coming to "PHP on its own"...
At that exact moment of shifting from 2006-09-15 to 2006-09-16 date "something"(on its own) should check tables and search for all userids that have expire date set to 2006-09-15 and UPDATE status of those users form upgraded to free.

I first time came to this kind of problem and don't know how to solve it.