Changing order from delivery to pickup

I have recently ordered a modem (and maybe some other stuff?) in accordance with my new apartment complex's included wifi. I am a bit frustrated, as I have absolutely nowhere to see exactly what it is I have just ordered. I spoke with an associate a few weeks ago before placing the order, and they said I would be able to switch my ordered hardware from a delivery to a pickup, because I am worried that the hardware will arrive before I am able to move in and be stolen or otherwise misplaced. Could someone help me figure out how to do this?