Excuse me, could we have a table over there by the wall? 请问，我们可以坐那边靠墙的桌子吗?

I'm sorry. That table has been reserved. 很抱歉，那张桌子已经被预订了。

Can we take that one over there? 我们可以坐那张桌子吗?

Could we change tables? 可以换个桌子吗?