4 STEPS
1 The first step is to click Subscription under Settings
2 Review Current Subscription Plan (in this case the client is using Voice Box Proof Readers) and click Change
3 To change, choose the subscription type that suits your needs - in this case "Using Your Own Secretary" and click Subscribe
4 That's it. You're done.
Here's an interactive tutorial for the visual learners
https://www.iorad.com/player/1644215/How-to-Change-Subscription-Type