Change the voucher into real train ticket

I wanna buy JR East Nagano Niigata area pass.

In the article stated that if i buy online outside Japan, i suppose to change from voucher into ticket in airport when i arrive in Japan.

But i want to use it on the 15th day from my departure.

Can i change into real ticket in the 15th day? So maybe change it in train station instead of airport. Since the ticket is active when i issued it and only last for 14 days.

And to make sure, i can use it in 5 days f choice within 14 days ya?

Thank you so much!

Pass to be used on later date? Why not? Actually, you can even exchange voucher for real pass the moment you arrive in Tokyo as long as you specify the date of use and the station pick-up.

The validity period of the JR East Passes begins on the day of purchase/exchange; it cannot be changed.

Ahhh so i'll change it on the day 15th ya. Because when i change it then the 14 days availability starts.