Q: Can I trade in a Sony watch for an Apple Watch ?

Not with Apple - what would they do with a Sony watch? Probably not with anyone else either, but if you could find a retailer who sells Apple watches as well as other ranges you might be lucky.

Hi,

Sell the Sony watch then put the proceeds toward an Apple Watch.

Hi

Whilst the Apple Renew / trade-in program does currently accept and potentially offer credit (whether as instant in-store credit or via Apple Store Gift Cards for mail-based trade-ins) in return for recycling some other brands of smartphones and other devices, the program does not currently include Apple Watch or any other smartwatch brands.

More information:

http://www.apple.com/recycling/