Redirecting port A to port B on the same machine on Linux

iptables -A INPUT -i eth0 -p tcp --dport -j ACCEPT
iptables -A INPUT -i eth0 -p tcp --dport  -j ACCEPT
iptables -A PREROUTING -t nat -i eth0 -p tcp --dport  -j REDIRECT --to-port

Reference:
https://wiki.centos.org/HowTos/Network/IPTables