Pivoting nursing specialties?

Has anybody completely pivoted their nursing specialties?? How far into your career and how did you decide to make the switch??

When I was a nursing student I was too scared to go for an ER nurse or tech position so I really missed out on my chance to experience how an ER operates and if I'd like it. I'm kicking myself now because I'm in NICU now but I would really love to seek out some ER experience too.

Should I ask for a shadow day at my current hospital's ER? at a different ER? I'm just worried I'm gonna be blow back from my managers ://

Bonus: is anybody more than 1 specialty? In an ideal world, I would love to keep my NICU job full time but be PRN at an adult or peds ED. Do you think units would hire me as PRN for the ER even if it means my orientation will probably will extended? Do they even hire like that??? Pls provide your input!! thanks :* <3