How can I go from QB online plus, to QB simple start?

Great day and welcome to the Community, @ultimatecoolingh. 

Let me share a few information before you downgrade your subscription from QuickBooks Online Plus to Simple Start. 

Please know that there are some features in your current plan that may not be supported on the other plans. Additionally, it might affect some third-party apps connected to QuickBooks and removes all the discounts you have on your current plan if there's any. Check out our comparison chart for more information. 

I'd also suggest you read through this help article: Downgrade your QuickBooks Online plan. It contains very important information that you need to do before you switch to another plan with more detailed steps on how to downgrade. 

Keep me posted should you need more assistance with the downgrading process. We're always around here to guide you.