I went to the Amtrak forum last night and found a discount promotional code for unreserved Philadelphia trains. I think the code was V707 (with the Miles forums down now, I'm just guessing).

I plan to take the train to Philly from Penn Station New York Sunday morning. I want to take the 11am unreserved train which gets in at 12:20pm. The train which leaves at 9am, however, is a lower fare than the 11am and thus, the promo code will of course get me an even better fare than I could get for the 11am with the same promo.

If I buy the ticket online for the 9am unreserved train, can I use that same ticket for the 11am? Or will it be deemed no good? Any help would be greatly appreciated. Thanks!