1. Login to your Customer Control Panel & click on Account from the left-side menu options: 

 mceclip0.png

  1. Click on Subscriptions:

 mceclip1.png

  1. Click on the relevant G-Suite subscription:

 mceclip2.png

  1. Click on Change Service Plan:

 mceclip3.png

  1. Choose the new plan & click on Next from the bottom of the page:

 mceclip4.png

  1. Adjust resources (licenses) if required & click on Finish:

 mceclip5.png