There is a standard open ticket which doesn't have any restrictions.

有一种标准开放的票没有任何限制。

" I have a one-year open ticket. I'm not sure when I'm going to go back, but within one year." Have that ticket ready to show him or her.

" “我有一张为期一年的不定期票。我不确定我什么时候回去，但一年内。准备好那张票给他或她看。