can't delete/change template files - Joomla! Forum - community, help and support

i use ws-ftp 9 transferring files, installed nes theme installer> template-site want change files in theme when try delete files of theme give smessage "550 not delete layoutconfig.php: permission denied" tery cnange permission of folders/files 777 still gives message "550 not change permson /public_html/templates/ed_education_portal/images_blue: operation not permitted"i can't thing plz help

install joomla explorer change permissions on files install joomla. not owner of file if joomla installs it.