Can I go to DD214 brief after starting terminal?

Kind of dumb question. Long story short, I ended up with non-refundable reservations right when I'm supposed to go to my DD214 brief the day before terminal. It's not going to KILL me if I miss the reservation but I'd really like to not miss it if possible. Anyone know if I can just go to the brief the following week while I'm on terminal? Does it HAVE to be the day before you start terminal? The paper they gave me says I can attend the briefing "no sooner than the last day before your transitional/permissive TDY begins." No mention of what the latest date I can attend is.