If you lost the chat support window, you'll need to open a new one. But don't sweat, your whole chat history will be on your account so the next agent can pick up where you left off!
I've included the steps below to connect back with another chat agent.
Open the Help menu at the top, then click QuickBooks Desktop Help.
Select Contact Us.
Give a brief description of your issue, then hit Continue.
Choose Chat with a live agent.
That's all there is to it. Please know anytime you have questions or concerns, you can always reach out to us here in the Community. We're here to help you get back to business. Take care and enjoy your day!