If there are existing transactions that you need to edit using the new rate, you'll have to manually open them individually and toggle them to the correct rate. Feel free to use this link for more details in handling your sales taxes: Edit tax rate in QuickBooks Online.
Please know that you're always welcome to post if you have any other concerns about changing your tax authority. Keep safe and have a wonderful day!
Need QuickBooks guidance?
Log in to access expert advice and community support instantly.