react router – How do i safely update my ReactJS build WITHOUT stopping NGinx server?

i have an Nginx server running on Ubunti. It’s currently serving fine, and my ReactJS application is running.

I need to update the /build folder of the ReactJS application. I don’t think i should reatsrt the Nginx server (as i’m not changing the configuration).

If i delete the /build folder at the root /var/www/..../build location what will the server do? Is that a bad idea? Or should I replace the /build folder (i.e build elsewhere and sudo cp -R build/ to the above location?).

Any best practice?