I am booking my first AA award (UA convertee) and wanted to see if someone could answer a gateway city stopover question for me.

The wife and I are looking to book our return from Vietnam for April 2015 on JAL Biz or First. I am told those seats need to be booked right away as there isn't much inventory. We are flying into JFK and want to use the gateway stopover and then late on continuing on to somewhere in the Caribbean.

So my question is, if we book in May (when the tickets open up) - is the ticket only good for 1 year from that date? ie will we have to continue our flight in May or could we change the date to later in the year?

Would rather spread out my vacations!