There isn't a customer-facing API for switching the drivers. One reason is that it requires admin capabilities, which most newer versions of Windows restrict for standard applications (like LabVIEW). This means that typically to switch drivers you have to launch a special process at elevated level (and Windows will give a special prompt to approve the action --- which by design can't be fully automated).
If you decide to pursue this route, Microsoft provides a development utility called "DevCon" that is a command-line utility that can switch devices between different driver packages (and could be called by LabVIEW). Additionally, NI internally uses a utility (C:\Program Files (x86)\National Instruments\NI-IMAQdx\Utility\switcher.exe) that serves this same role, but it is a bit trickier to use manually since it is designed to be used without a window or console and expects other code within the application to do some of the bits that don't need administrative capabilities. It's arguments are also not documented and could change at any time.
