Someone asked the same question going the other way quite recently:
Other direction but the principle is the same - cash accounting works with payments whereas accrual works with invoices, so you’ll have to make manual adjustments on your first post-switch return to make sure everything is accounted for exactly once and nothing twice.
You’ll have to exclude any sales or purchase invoices dated before the start of your current quarter, add back any that were raised in previous quarters but not paid until this one, and also exclude any that were raised this quarter but paid in advance before the quarter start. And that’s assuming no partial payments.