Given that you are changing the credentials, you already have a Docker container running with a mounted volume.
  1. Stop the Docker container.
  2. Start the Docker container. In the docker run command, specify the desired following environment variables using the --env command-line option:
    • --dbAdminUsername
    • --dbAdminPassword
    • --dbAppUsername
    • --dbAppPassword

    Also specify -p, -d, --env-file, --volumes-from, and --env PING_H2_FILE.

For example, if you have a container named pap with a mounted volume as shown in the example in Deploying PingAuthorize Policy Editor using Docker, the following command changes the credentials for the admin and application accounts from their default values to admin / Passw0rd and app / S3cret, respectively.
Note: For proper communication between containers, create a Docker network using a command such as docker network create --driver <network_type> <network_name>, and then connect to that network with the --network=<network_name> option.
docker run --network=<network_name> -p 443:1443 -d \
  --env-file ~/.pingidentity/config \
  --volumes-from pap \
  --env PING_DB_ADMIN_USERNAME=admin \
  --env PING_DB_ADMIN_PASSWORD=Passw0rd \
  --env PING_DB_APP_USERNAME=app \
  --env PING_DB_APP_PASSWORD=S3cret \
  --env PING_H2_FILE=/opt/out/Symphonic \
  pingidentity/pingauthorizepap:<TAG>

The Docker image <TAG> used in the example is only a placeholder. For actual tag values, see Docker Hub (https://hub.docker.com/r/pingidentity/pingauthorize).