Movide website from root directory to main.

Can anyone please suggest the steps to move my website from root directory to main directory, for example (https://example.com/demo) to https://example.com

i have already hosted a site on https://example.com i make my new website and launch it at subdomainhttps://example.com/demo , but now i want to move new website to the main domain, Without uploading all the files to the main directory.As files are placed in sub directory already.

Please suggest something good.

Thanks in advance