You're right, Robert. The option to Reclassify Transactions is located in the Tools section under the Gear icon. However, please note that this feature is only available for QuickBooks Online Advanced and QuickBooks Online Accountant subscriptions.
This feature isn't available in the Simple Start, Essentials, or Plus plans. If you're not on the Advanced or Accountant subscription, you'll have to reclassify transactions manually, editing each one individually.
If you require the ability to reclassify transactions in bulk, you might consider upgrading your subscription to QuickBooks Online Advanced or QuickBooks Online Accountant.
If you need help with your QuickBooks tasks, click the Reply button. We'll assist you as soon as possible.