You can change the currently active theme from within SSH. This is a more advanced method, but can be more efficient for developers who manage multiple WordPress sites.
Connect to MySQL using the following command:
mysql -u username -h hostdatabase -P port -p
Enter the database information from your database as follows:
Once connected, enter the following command to check your current theme and child theme:
select * from wp_options where option_name = 'template' or option_name = 'stylesheet';
To change the template, enter the following command
update wp_options set option_value = 'themeName' where option_name = 'template';
Update the command as follows:
To change the stylesheet, enter the following command
type update wp_options set option_value = 'themeName2' where option_name = 'stylesheet';
Update the command as follows:
After changing the template and stylesheet, type exit; to close out of SSH.