Port Redirection

How can I make a local port listen to another port? I basically would like to connect to a Minecraft server, on port 25565 from an unblocked port like 443.

Just change the port in the MC config.

Or if it is behind a NAT router, forward 443 to the server's IP address and port 25565.

how would I go about forwarding it to the server's ip and port? \

I'm assuming that you are trying to access the minecraft server from a computer outwise of your home network e.g at a friends or at school. So...
On your routers web interface there will be a section for port forwarding.
There a great website call Portforwarding.com on there there is a long lost of routers and there should be a guide for your specific router.
Here's a nice diagram of what will be happening:

Internet --443--> ROUTER ---25565--> Minecraft server

I'm not allowed to access/reset the router itself D:

dang,
If the router supprot UPnP you might be able to set a mapping using this tool
There a handy guide here also to set this up. Other than that that's probably your only options.

btw, you shouldn't have much problem setting up minecraft to run at 443.

How does it work?
Your outgoing gateway is open at port 443, there is no way for you to let people connect at 25565 because router doesn't allow it. IF you don't have access to NAT/PAT on router you cannot do anything.

I ended up buying a good, local vpn :) and connecting to it through a sstp