Alternatively, if you don't have both your PS4 and Pro available at the same time, back up your PS4 to an external hard drive and then restore your PS4 Pro from the back up when you first boot it up.

This is what I did as I sold my PS4 to the same store I bought the Pro from.

Back up (around 400 Gb storage used on my PS4) took roughly 5-6 hours. The restore on the pro only took around 2 hours.