Excuse me. Where s the rest room?  请问女卫生间在哪里？

It's outside the hall. 在大厅外。

Where’s the powder room? 女卫生间在哪里？

Excuse me, madam. Where’s the powder room?  打扰了，女士，请问女卫生间在哪里？

Oh, I’m just going there. Follow me, please. 哦，我正要去呢，请跟我来。