I'm not sure this is what you meant, but just to be on the safe side... By what amount? If you changed your chainring & cassette by four teeth, that doesn't mean to remove four links from the chain. There's not a 1:1 correlation between links and teeth.

Unless you've done the math (e.g. finding the circumference of the chainwheels old and new, determining the amount of said chainwheels engaged with the chain, and figuring the difference), I'd recommend buying a chain a few links longer than you think you need, then measuring it in place and shortening it to fit.