The first half of the 2 hour season premiere is called Good Morning and the second half is called Goodbye. The episode airs on Thursday, September 24.
Here's the episode summary:
The hospital staff is left to deal with the aftermath of George’s passing. Hitting the staff hard, they all find unique ways to get through the various stages of grief. George’s mom returns, faced with the difficult task of deciding what to do with his organs. In the second episode, entitled “Goodbye”, time has passed… Everyone is struggling after losing one of their own and are turning to any distraction they can find. Meredith and Derek seem to be consummating their marriage anywhere and everywhere, while Cristina and Owen have been instructed to abstain from sex by Dr. Wyatt. [BSCreview]Source