Currently, there isn't an option to change the liability period of your payroll taxes once you've already recorded it.
In addition, if cases like yours happen again, you'll have to record your sales tax refund on May since you received the actual refund in May.
Thus said, you can follow the detailed steps outlined by my colleague, @PreciousB, above in recording your sales tax refund.
Lastly, you can also read this article which can be your guide for any future tasks: Sales tax in QuickBooks Online.
It'll be always my pleasure to help if you have any other questions. I'll be keeping an eye for your response.