How can I change from Plus to Essentials and not lose any inventory items?

Welcome to the Community, @linda-evergreenn.

I'll be pleased to provide you with the QuickBooks Online (QBO) Essentials pricing and the process of how to downgrade. 

You have to inactive the inventory first before you can turn off the inventory. However, not losing any inventory after downgrading the plan is not possible. 

Here are the things that we need to do before downgrading:

• Remove extra users. Each plan has its user limits.
• Turn off inventory. QBO Essentials doesn't support inventory tracking.
• Run and save all your products and services reports so you have a record of your current quantities on hand.
• Deactivate your inventory. When you downgrade, your inventory's quantities reset to zero.
• Cancel any third-party apps if there are any in cases your new plan no longer supports them.

About QBO Essentials' pricing, you can refer to this link for more information about the plan and its available features: QuickBooks Online Essentials.

To downgrade your plan:

1. Go to the Gear icon and select Account and Settings.
2. Select Billing & subscription.
3. The highlighted one is your current plan.
4. Click on Downgrade your plan then review the available plans.
5. Follow the on-screen steps to downgrade your plan.

In addition, you can check this article that'll help you in case you need to update your payment method and change your billing schedule: Manage billing, payment, and subscription info in QuickBooks Online.

I'll be right here if you have more concerns about downgrading your QBO subscription. Have a good day!

@linda-evergreenn 

Before downgrading your plan to Essential, you can convert your data to get a QB Desktop file format. All inventory, cost of goods sold, purchase, and sales account info will convert. Then you can use the trial version of QB Desktop to access your historical data for good.