If your customer can't see the 'Exchange' option when it should be available, review your settings to identify potential blockers.
Common reasons:
In Settings > Exchanges, if 'Block if selling price is not equal to original' setting is enabled, the customer won't be able to exchange items purchased at a discounted price.
In Settings > Exchanges, if 'Block if selling price is zero' is enabled, customers won't be able to request an exchange for an item that has already been exchanged.
If these settings are causing issues, adjust them accordingly to allow exchanges as per your policy.