Once done, you can now disconnect the US dollar account to delete all its transactions. Just select the Trash icon in that section within the Bank accounts page (see the screenshot below). Please take note that this process is permanent.
If you're trying to change the subscription payment method from a US dollar account to Sterling UK money, this is currently unavailable in QBSE. The card must have a US-based billing address, so I'd suggest looking for another one with the same country. To help you guide you through the process, see this article: Update Billing Info.
Lastly, I recommend visiting our resource hub to help you effectively manage your QBSE subscription.
The Community and I will be here to help if you're referring to something else or you have other concerns. Keep safe always, and stay healthy.