To change the password of your UI account, you need to login with the admin account,, navigate to server management >> Security, pick the account and update the password, please see the attached image for reference on this.
I assumed based on RBAC you created another account and you are not using the root admin account for your UI activities. If your main admin account is what you need to reset, Please refer to the
password management for single user documentation.
You will need to download the password tool before you can proceed with this activity: