Returning opened store-bought Apple Watch

I bought my wife an Apple Watch for her birthday (GPS/Cellular), which she opened on the big day.

She likes it, but would perhaps like to return it (probably to use the money for another Apple product).

The manager at the store told her, however, that the watch couldn’t be returned as it had been opened.

Apparently the returns policy for online purchases allows you to return opened products/watches within 14 days.

My question: is there any chance of returning the watch and either getting a refund or a credit note for the full amount?

Grateful for any feedback; thanks,

Stephen