I don't think that was what Zenzefiloan meant, but I could be wrong...
If you just want to erase and reformat the partition, you can do what djohnson suggested. In fact, you could do that right from OS X.
If, on the other hand, you want to remove the partition so that it's space is added to your OS X partition, you need to repartition the whole drive. You will erase everything and all partitions on the drive if you do this, so back up what you want to keep. Be aware, though, that there are no easy ways to back up an OS X drive completely (a lot of hidden files won't be copied).
Unfortunately there is not a way to change partition sizes when using Apples drivers on your hard drive. Making any adjustment erases the entire drive.