If the websites are bing managed in GoDaddy. Have your new administrator signup for GoDaddy Pro.
If you use GoDaddy Pro, you are able to delegate access to that one account and all the services and products in it. If that account has a Linux hosting with multiple websites, they will have access to those websites. If that's the case, you should use cPanel to manage access via FTP instead.
If you want me to be more specific, please give more details. Are the websites in separate accounts? Are they in web/WordPress hosting? Linux hosting? VPS? Dedicated?
On a side note: If your domain's name server are also being managed by the website's host, they may get full access to your subdomains as well. Just keep that in mind.
Hi there @mnanette,
That's odd. BTW, some FTP clients default to SFTP so make sure you selected FTP and port 21. Also, double check that you are using the correct IP. Using a ftp.domain.url to resolve to your FTP IP doesn't always work either. Otherwise, call support.
To log in through FTP (FileZilla). You should know the primary credentials of your web hosting. Follow the video tutorial below.