If you are talking about the modem that AT&T supplies you when they set up the Internet, no. It is their property and you have to return it to them. Plus it would not be configured to work at your new location. If you plugged it in it would not connect. AT&T (or whoever your provider will be at the new location) will supply a new modem for you.
However if you mean a wifi router that you purchased, you can take that with you. And once attached to the modem at your new location it should work the same as it does at your current location.