It can be done, but it depends on your landlord. You'll have to be ready to tell them why they should lower it, first. One way would be to see if similar properties are being rented for less or are offering better benefits (same rent, but free utilities or something like that.) If you can prove that they're charging more than they should, they might come down a little. If you've been there for a year or more and they consider you to be a good tenant, you could also say that you found a cheaper place and you'll move when your lease is up unless they match the price.