How to mask redirect subdomain and ports to another external subdomain on that same port

I have read through the forum but still cannot get a clear answer for what I need.
My purpose is to mask redirect a subdomain to another one with the port passing together.
For example, I want my vdi.mydomain.com:445566 redirect to other location at client.cloud.example.com:445566 (The port is the same)
Basically, I want to connect a RDP session to someone else's server on special port. I want to use my url instead of others. And I prefer mask the destination url if possible. I have all domain control on my side. Any help? Thanks!