cd not eject and how to remove the cd unit

I have a Nissan 2004 Sentra. The CD will not eject. How do I remove the unit from the car? I do not want to break anything.
Thanks.

2004 radio removal.
1) remove the lower piece that wraps around the center It's a small piece the same color as the dash board (it's just held on by clips).
2) pull the tray from the dash, there are no screws just carefully pull it straight out (hazard switch is attached so pull carefully).
3) remove the two screws you can see after removing the tray from the dash. there are two phillip head screws on either side of the radio
4) behind the lower piece of the dash you will see 4 more screws remove the two that hold the face plate for the heater control, then remove the bottom two and the whole bracket that holds the radio in will come right out.
It took a while to figure this out, and the dealer was absolutely no help.