Just run the setup script as follow:

 # /var/www/imscp/engine/setup/imscp-reconfigure --reconfigure

This will cause all questions already seen to be show again.

If you want to specifically change something such as the main IP address for the control panel, you can use directly the primary_ip flag and just answer the questions.

  # /var/www/imscp/engine/setup/imscp-reconfigure --reconfigure primary_ip

You can type −−reconfigure help for get a list of all reconfiguration flags.