Our company uses AWS, however the owners are not technical people. Legal aspect aside, is it possible to gain access to an AWS organization if the CTO doesn't want to give back username and password?
Let's keep in mind that private keys, cli access, ARM everything is on CTO's hand.
If so what is the procedure?
I would expect the process to be similar to what AWS documents for recovering access in case of a regular employee with administrator access that has left the company. See:
https://aws.amazon.com/premiumsupport/knowledge-center/admin-left-need-acct-access/
That of-course assumes that a corporate e-mail address was used to set up the company AWS account. If a personal e-mail account was used that approach won't work.
And related:
https://aws.amazon.com/premiumsupport/knowledge-center/transfer-aws-account/