You may use the pot file to change it. See related article: https://support.ellethemes.com/?ht_kb=translate-site-using-po-mo-files
Or change it directly from the files. Go to files: tower\includes\view\blog\ All files here. Look for code like this: <a href="<?php echo get_permalink() ?>" class="read_more"><?php _e('Read More', 'tower')
Find the string and change it. Make sure to change all the text. The “read more” could be present in the file multiple times, if you change only one, then you may not see any change in the site.
