(a) If a tender or delivery by the seller is rejected because nonconforming and the time for performance has not yet expired, the seller may seasonably notify the buyer of the intent of the seller to cure and may then, within the contract time, make a conforming delivery.
(b) If the buyer rejects a nonconforming tender that the seller had reasonable grounds to believe would be acceptable with or without money allowance, the seller may, if the seller seasonably notified the buyer, have a further reasonable time to substitute a conforming tender.