How to change WordPress multisite mode from sub-directories to sub-domains?

Question

Domain name market

During installation, the subdirectory mode was selected, 5 sites were created, MU Domain Mapping was used, it became necessary to return the ability to create sites on sub-domains, how to do it with little bloodshed? besides replacing .htaccess and replacing define('SUBDOMAIN_INSTALL', true); to true ?

Answer 1

Taken from the Codex
If you installed WordPress more than a month ago, you will only be able to access subdomain mode when you try to activate the network. This is done to prevent possible conflicts between pages (eg example.com/pagename) and sites (eg example.com/sitename). If you are sure that this problem will not affect you, after the installation is completed, you can change the mode.
Change the SUBDOMAIN_INSTALL setting in wp-config.php:
Use Subdomains
Use Subdirectories
You will also need to update your .htaccess for the new mode. Keep in mind that if the site has been working in one of the modes for some time, then changing it can lead to problems, so be careful.