SQL 2008 and 2014 side by side

Hi

I have 2008 std (instance DB-SERVER) and 2014 std (instance DB-SERVER\SQL2K14) on the same machine side by side. I am trying to configure tcp/ip for the 2014 to be able to access it remotely over LAN. In Configuration Manager for tcp/ip setup I have used the same default port 1433 for both instances. Problem is this makes one of the instances to fail to start with error;

Server TCP provider failed to listen on [ 'any' <ipv6> 1433]. Tcp port is already in use.

What is the correct way to configure both instances so both are accessible over LAN via tcp/ip?

Thanks

Regards