do you mean, that you would like to deny the possibility for the customer - -ftp - user, to change the permissions for files and folders, when he/she uses a FTP - Client?
Pls. note, that IF you desire to change group permissions ( for groups like "psacln" or "psaserv" for example ), it can result in issues/errors/problems and could destroy the functionality of your vhosts structure for all domains hosted on your server.
I want to change the permissions only for a one ftp client account over one folder. I don´t want to change group permissions or change another ftp permission