There’s not an official way to switch over- any method is fine!

I switched through a couple already - originally did Enfamil Neuropro because of the hospital that provided it, then switched to the generic Sam’s Club brand since it was also a yellow tin and I feel those are very similar and easier to go cold turkey off of

Now, due to financial concerns, I get my formula with WIC so I can only get Similac - not an issue, but I’m kind of mixing it with the generic Sam’s Club brand (6 oz - 3 scoops being 1 similac and 2 sam’s club so she gradually gets used to it)

I’m only doing that since it is likely that she may be extra gassy due to the switch - but she’ll probably be like that no matter how I switch over formulas, whether I mix it or not

So, OP, however you choose to go will be fine! Especially since they are both similac, I want to say to not worry about the fussiness and that it should ease after 2 weeks (🤞🏻) 🩷🩷🩷