Because we can’t hire an additional person, I’m being asked to choose who to fire, so we can hire someone instead.

So we need a person who can do sales and has experience in that. But we can't hire a new person, because of the budget limits and etc. So I was asked by my manager to choose one of the existing workers, that are doing some other job in a different department – to fire em, in order to hire a new person. Not sure how to act or react