“但是也有可能改变行程” 英语怎么说？？

Question

“在出发去前的一个星期，我才能知道确切的行程安排”。这句话英语怎么说？

Answer 1

But the schedule may be changed

I can know the exact schedule one week before the trip

Answer 2

I wouldn't be sure about the exact schedule until the week before departure.

Answer 3

In the set out to one week before, I can know the exact schedule