I'd like to reconfirm my reservation on Flight 516 for Hong Kong at 2 o'clock, June 18th. 我想确认一下我预订的机票，6月18日两点起飞去香港的516次航班。

You are confirmed on Fight 516. 您确实订了516次班机的机票。

I'd like to reconfirm my reservation. 我想再次确认我的预订。

Yes, I'd like to reconfirm my reservation. 是的，我想再次确认我的预订。