Even though the vast majority of college roommate matches end up working out just fine, there are always a few exceptions to every rule. So what happens if you end up not liking your college roommate?
Rest assured that there will always be options for you if you and your roommate don't seem to make a good fit. First and foremost: The issue is going to have to be addressed. You can try to address it yourself by talking with your roommate, or you can go to someone on your hall staff (like your RA) for a little help. They'll listen to the problem and see if it's something that can be worked through and even help you figure out how to talk to you roommate about the problem(s), with or without a staff member present.
If your roommate conflict can't be resolved, you'll be able to change roommates. Keep in mind, however, that this can take a little while: a new space for one of you will have to be found. Additionally, it's highly unlikely at most schools that you'll just get to live by yourself if your original roommate situation doesn't work out, so you'll have to wait until another roommate pair wants to switch, too. Lastly, some schools won't let roommates switch until a certain amount of time (usually a few weeks) has gone by since the semester started, so there may be a delay if you decide you don't like your roommate early in the year. Just keep in mind that the hall staff wants everyone in the halls to be in the best situation possible, so they'll work with you -- in whatever way seems best -- to come to a resolution as soon as they can.