It would be nice to change the device address of a NI 2503 Switch board. I have several NI 2503 Switch Boards in my PXI 1006 Chassis. After installing the boards and performing a MAX Refresh the device addresses of the boards are listed in a random (?) order. So its troublesome to get the information which device is related to which slot. I have more than one 1006 Chassis with the same configuration of NI 2503 Boards and I may avoid to have different software versions with different device numbers for the chassis.
The short answer is no you can't modify the device numbers for the switches. The long answer is that device numbers are set by the bios and you can't modify them. In your 1006 chasssis there are 3 buses and in each bus the devices start at some number like 15 or 20. As the slot number increases the device number decreases. The best way to view what device numbers are assigned to which slot you need to open the pxisys.ini file on your computer. The slot number and device numbers are total dependant upon your controller. The best place to verify that you have the correct ini file is to see the following webpage : PXI VXI/VME and PXI Controller Peripherals. The ini file is only an indicator of the settings in the bios. If you change any of the devices then you will lose functionality of that board. There is some hope though. One thing that you can do is use the IVI support for the switches. If you download the Class Drivers for switches, then you will be able to create an IVI devices and logical names in Measurement and Automation Explorer (MAX). The IVI devices will hold the address of the module (i.e. PXI0::14::INSTR). Then create a logical name that points to the IVI virtual device. This logical name can then be referenced in LabVIEW instead of the module address. Then when you need to modify the slot number/device number of a device you simply need to modify the IVI device. There is a tutorial that will step you through this process found in the Developer Zone at : Using Measurement & Automation Explorer to Configure Your IVI System