returning diapers without knowing where they are truly from

So at my baby shower I did the diaper raffle and I was overloaded with diapers so with that being said it's almost time to try and exchange some smaller ones for bigger ones! I don't know where the diapers were truly purchased from but they are all name brand like huggies and pampers. Does anyone have any suggestions on where to go? Like Walmart or target? I will be just exchanging for bigger sizes I don't want money back for them.