Create a .vbs file (name it DefaultPrinterChanger.vbs or something else) and change the default printer name to the name of the default printer you need.

Set WSHNetwork = CreateObject("WScript.Network")
WSHNetwork.SetDefaultPrinter "HP Printer"

You can also call this script from a batch script; for example:

@ECHO OFF
TITLE Change default printer
Cscript C:\voorbeeld\DefaultPrinterChanger.vbs