Can I swap an iTunes gift card for an Apple Store gift card? (Both digital versions)

Hello.

Wondering if anyone can help/advise.

I bought an iTunes £50 voucher online as a present for my sister, thinking she could redeem the value towards buying an iPad.

I opted for the code to be emailed on the day of her birthday, which is today.

However, I've just learned that I should have bought an Apple Store gift card... How confusing.

Will Apple likely be able to transfer the balance across? And if so, how do I do it?

Any help would be greatly appreciated.

Cheers,

Steve