How do I reset so that I can use multi-currency, as the only entry so far is the USD main currency opening balance?

You can always change your home currency if you haven't activated the multi-currency feature in QuickBooks Online, Elizabeth. I'll share some insight on how to manage your domestic currency below.

Before we begin, it's important to check the status of your multi-currency feature in QBO. This will determine if you can still modify your home currency rate within your account or not.

If the Multi-currency feature isn't enabled, you can follow the steps provided below to check and change your home currency in QBO:

1. Navigate to the Gear icon, and then select Account and Settings.
2. Go to Advanced.
3. Scroll down and choose the Currency section, then click Edit.
4. Look for your preferred home currency rate in the Home Currency dropdown.
5. Once done, Hit Save, and Done.

However, if the multi-currency option has been enabled, there will be no option for you to modify your home currency. You can only change your home currency by deleting all your data and start over in QuickBooks Online.

Additionally, you can check this page to learn how to move your existing lists to QuickBooks Online from another QuickBooks Online company. This saves you from having to set up the items from your lists one by one: Move your lists to QuickBooks Online.

Lastly, here's an article you can visit for more details on managing multicurrency, including adding, deleting, or depositing transactions with different currencies: Set up and use Multicurrency in QuickBooks Online.

Please know that you can always revisit this thread if you've further questions regarding home currencies in QBO by clicking the Reply below. The Community is here to help.