It depends if you bought it from that store and if you still have the receipt. If you do then you should be able to exchange it however it may not cover the whole cost of the new product.
If you have the receipt, it's best.
You can return it. Exchanges are not permitted. Then you can repurchase the size if they have it if not then at least you were able to return what you didn't need.
Actually should call them and check the stock to see if it's available
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