How do you change units from NICU to ICU?

I have been a NICU nurse for two years and love it but want to move onto adult ICU. How do nurses change units? Don't I need to get into an orientation program? I'd love to work in a cardiac ICU most of all.

BTW NICU isn't bad as far as ICU experience is concerned. I take care of very sick micropreemies.

One thing that I know I will miss if I leave the NICU is the tiny mess/diaper. If I leave, I have to clean up big people!