Exchange Apple products not purchased at Apple Store

OP, please explain what you mean by "exchange".

If it is a warranty issue, then Apple will handle the "warranty exchange"; contact Apple support.

If you just want a different device (color, model, etc), then you will have to do that through the original seller and meet their requirements (time frame, restocking fee, etc).

You talk to the store where they were purchased.

Apple has a return policy for product you buy directly from them but, if bought through a third-party outlet, refers you back to the reseller that sold them.

See: Returns & Refunds - Shopping Help - Apple

especially this part: