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Hi AtlasGlobal! Great questions. You do not want to assume the old listings for the former brand, as their reputation belongs to them and not you. Rather, I recommend that you read this post https://searchengineland.com/business-owners-guide-moving-office-234671 and follow these steps outlined in this post for what to do when a business moves: https://moz.com/blog/delete-gmb-listing. I would follow those steps in dealing with the GMB listings, and I'd recommend updating any existing  Yelp listing manually for your client, and then I would use Moz Local to get the new info out there on the major aggregators + other critical platforms.