Hi, as it's a newly acquired business you may want to give yourself some time before changing any procedures. I would rather refer to improvement than change - and involve the existing staff in coming up with improved procedures. As others have also put it, it depends on the procedures you are looking to "change". At the end of the day, it makes sense to ask employees how they can make their work better / easier / more productive - they're the ones who've been doing the work, they might come up with some good solutions to improve processes.
Happy to help further if you're able to share more information.