How do I change the NAS so that I can access its web interface from outside of the subnet?

Hi, I am currently using the NAS in an office environment, and it is not sitting on the same subnet as my computer in my office. I still have ssh access, since fortunately I set it up before the subnet changed and the NAS received a static IP address. Now I want to be able to change the NAS configuration so that I can access its web interface from any IP. I want to do it through ssh – what is my way of doing that? Thanks.

Hopefully an experienced User will be able to assist.