Migrating App to new Image question (newb)

[wcmgto]

I'm a complete newb with all things okd, Kubernetes, Docker, etc... I built an OKD cluster to play around with and to just get a feel for it. I'm currently testing creating apps and I have what is probably (hopefully) a very basic question. I created a wordpress app using the s2i strategy with the centos/php-73-centos7 image on dockerhub. I'd like to test upgrading this to a new image running PHP 7.4 (maybe using the ubi8/php-74 image) without losing changes to the wordpress site. I can't for the life of me figure out how to do this or if it's even possible. Can anyone tell me if this is doable and what the process is? I'd like to learn how to do it in both the okd web console and command line.