There are several ways to break up a broody.
You could just let it sit until it gives up, but some will never give up.
Some people remove all the eggs and bedding. Mine will sit whether there are eggs or not.
I personally just lock her out of the nest and put her with the flock again. She usually starts squeaking at them, stays for a few minutes, and then runs to the pen again. She walks round and round the pen many times before giving up. We have two pens, and only one is fit for broody girls or mothers, so for the night she sleeps in the other pen. (They are free-range for the day.) Eventually she forgets about the whole broody business and goes back to laying. Of course, she might go broody again within a few months, but the sooner you break her up, the easier it will be on her.