Same thing with changing Kitty's cat food. No weening. Nor with Charlie's bad reaction to the regular Pedigree dry food or other types.
I had to try various brands before I bought Pedigree Healthy Weight. It isn't easy to find. Walmart sometimes, Amazon, but not at Chewy.
I gave away a lot of cat & dog food when I had an animal with a bad reaction.
Good luck again.
Love All Life; Thank You For Posting! :)