Yes, you can try that. But as you are seeing the delays and people fearing about the 2nd fp notice. I don't think that is a good idea. Your fp expires in 18months. And currently they are still doing Jan02, with still some oct,nov,dec,2001 cases pending. So I don't know how long yours will take. if you assume that it moves month to month, it will take atleast 12months to get to your case. But they are moving slower than that.
My recommendation is postpone it saying that you will not be available on those days, and then you will receive another notice and then go for it.
If you still insist on going early, you can just walk in and say that you have some travel plans. Request, don't demand. My friend took it granted and walked in and had a bad experience. I walked in with travel itenary and requested them and they accepted with out any problem.
