She spoke in a tone of voice that she usually 'reserved' for her students. [=that she usually only used for her students]
I will 'reserve judgment' [=will not make a judgment/decision] until I know the full story.
We 'reserve' the right to make further changes to the agreement if necessary.
(..) this time, the evidence was conclusive. The evidence... The evidence... Mr captain, you forget that we are on the front. Seems you are a reserve officer. Otherwise, you wouldn't talk like that about such a crime. Yes, you are right. I was a lawyer in peacetime. But now... I'm a reserve officer too! (..)1965 Forest of the Hanged