How to replace or renew certificate on TCP9200 and TCP9300 ?

Hi All

    Production AA Server has been upgrade the latest version (6.4.3.1)

but it still been detected some vulnerabilities...

one point is TCP 9200/9300 ,both port use certificate...but it have expired 

we need upgrade it by using self sign certificate or using externale certificate to replace.

Who know how to renew or replace it ?

thanks!!

Wencheng