QuickBooks Enterprise has a very helpful feature that allows you to have two QuickBooks company files open at the same time.
Located within the File menu, you will see the option that says "Open Second Company" as shown in the screenshot below:
This literally allows you to easily jump back and forth between two company files without having to close one and open the other.
Please be aware that there are some limitations within the software of having two files open at the same time. You can review the complete list of these restrictions at the QuickBooks help site.
LEARN MORE ABOUT QUICKBOOKS ENTERPRISE...
I have some additional resources to help you better understand the additional functionality offered in QuickBooks Enterprise: