How I pass the viewer.camera.position on viewer.flyTo()

I was implementing 2D-> 3D functionalities. I will focus on the current position then when I switch to 3D it will just tilt the camera in current position. I tried converting the viewer.camera.position to Entity so that I can pass it to viewer.flyTo() but nothing happened. Any tips or guide to achieve what I’m trying to do?
Appreciate anyone who can help. Thanks!