Change WP-ADMIN
# BEGIN WordPress
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]
#these 3 lines change wp-admin to pop-admin
RewriteRule ^pop-admin/?$ /wp-login.php [QSA,L]
RewriteRule ^pop-admin/register/?$ /wp-login.php?action=register [QSA,L]
RewriteRule ^pop-admin/lostpassword/?$ /wp-login.php?action=lostpassword [QSA,L]
#############
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>
# END WordPress