1. Download all website files to MODX on a PC, in any folder, let it be packs name MYMODXSITE.
2. Make a backup of the database (in uncompressed form) and fill up in the same folder (MYMODXSITE).
3. Next, go core\config open with notepad++ (if not then download and install it, it's free) the file config.inc.php in notepad++ go to the Search tab, Find in files, and in the opened window find the line $modx_core_path= 'path'; in the find what field, specify the path (no under folders, core, etc.) in the replace box, specify a new path. usually it is something like this /home/w/.../your-domain/public_html/ path depends on the host, and specify a folder (MYMODXSITE) in which to search for files and then click "replace in files".
Note: If the domain of the Russian Federation, it must be specified in punycode (xn--80aaahhds2brf.xn--p1ai).
So first remove all the contents of the folder \core\cache well in your case as I understand it from assets/cache too, all you need to remove!
In principle, all Notepad shoveled all website files and will replace the old addresses on the new (and in files and in the database), and can transfer)