Recording Second Greeting on iPhone

Is there a way to record 2 greetings to my voicemail on my iPhone? Next month I will be taking a week off from work and I wanna to put a greeting on my phone saying that I am on vacation but still checking voicemail and email. Once that week is done and I go back to work I would like to be able to switch back to my current greeting that I have on my voicemail which I like very much. Anyone know the answer to that?