Usil's way is absolutely right.
For mine (not an UPO), once the pin was on it's way with the removal tool, I knocked in a removed pin back into the other side to get both half way if that's another possible option for you. I should hasten to add, take the bracelet completely off the watch, all this banging isn't great for it.
Taking to a professional for $10 is an absolute bargain.....as long as they are an actual professional. I took one to a watch place, paid, and they bust the clasp and generally buggered the whole thing up (bracelet later fell apart). Some of the mall guys are a waste of time...