How can I send the modules of M9485A to Keysight?

As the calibration is done for each module independently, remove the modules from the chassis and send them to Keysight.
Procedure (Recommended)

1. Remove all cables and dividers from modules.
2. Remove the modules from the chassis
3. Send the modules to Keysight. The cables and dividers are not necessary to return.

If you want to send your whole M9485A with the chassis, follow the procedure below. An extra handling fee will be charged.
Procedure (Optional)

1. Prepare a PXI cover per chassis (PN M9018-00206)
2. Make sure if the screws on the modules are tightened firmly.
3.  Make sure if the screws on the divider are tightened firmly.
4. Make sure if the cables are tightened firmly.
5. Place the PXI cover on the chassis.
6. Send chassis including all the modules and cables with PXI cover to Keysight service center.