They will always accept rescheduling, you don't really need a "valid" reason. I don't think there is a way to know when will the appointment be rescheduled for.
If this was built on a fair and logical system and an immigration law that considers real priority, I would get priority in my naturalization process, as my work-based green card was through an EB-1, where I went through an incredibly rigorous evaluation to prove that I am an "alien of extraordinary ability". But I'm getting no priority in naturalization whatsoever, so it has nothing to do with logic or fairness or rewarding those that same law considers bring exceptional value to the country. It's just a mostly random system. Anyway, I'm done venting and thanks for your reply.
Meelo12 got a reaction from TZKA in N400 June 2019 Filers
Meelo12 got a reaction from kline19 in N400 June 2019 Filers