Uploading code while USB is in use

I have an arduino micro that is inside a case, and it uses the usb to send serial data to a Android device. Would it be possible to upload the code to the board using ICSP while the usb is in use?
The main reason is that the case is inside a dashboard, and almost impossible to open it without dissmantling half of the dashboard. I would like to be able to upload the code on the board without having to open the case and swith the usb cables.

That sounds quite possible as long as you are not using the ICSP pins for anything else in your project

Note that the pins on the ICSP header are shared with other pins on the Arduino

If I am using the SCK, MOSI and MISO to communicate with another slave module, would that interfere with the code upload? I am thinking that when the reset is applied, the other module stops communicating with the Pro Micro?

SCK, MOSI and MISO are, of course, part of the SPI interface and if that is what you are using them for then I think that you should be OK, but try it

I was more concerned that you might have sensors or other devices connected to those pins that might interfere with programming

I'm not sure what you mean with 'while the usb is in use'. If you upload code via ISP, the micro is in reset mode, so no code is running. The usb connection to the pc will be broken.

I was not sure of that.