Before you can disconnect or switch your Stripe account. You must NOT have any events actively open for registration attached to the current Stripe account, i.e. the status of your event is "PUBLISHED"
Head to your Organizer Settings, click on the Integration tab or click here
Scroll to the Payment Processor and click "Disconnect" or "Switch Account"
If you're switching accounts, add your new Stripe account first. This will limit your down time and allow you to quickly swap over and keep your event from missing any payment opportunities.