In case you want to change globally a user password for all your Wordpress sites inside your machine and you want to change it in a single operation without having to visit all those Wordpress sites, here is how you can do it.
Wordpress: Global user account password change option with Core-Admin
To complete this password change operation you need a machine administrator account.
Get into your Core-Admin with your platform or machine administrator, then click on the selected machine and then launch “Wordpress management”.
After that, click on global account change option:
Then you will see a dialogo where you can input the user you want it to be searched over all Wordpress sites inside your machine and for who you want it to have its password updated:
After that finishes, the tool will give you a report about the operation done, Wordpress sites found/inspected, hostings, etc.