If there is a deficiency which can be remedied with economically reasonable measures, the buyer must request an improvement, however the chosen remedy may not be disproportionate (unreasonable) for the deliverer. If the deficiency cannot be remedied, the remedy is infeasible or unreasonable for the buyer or if the improvement is refused or inappropriately delayed by the deliverer, depending on the relevance of the breach of contract, also redhibition (reverse transaction of the contract, thus product or service for money) or in the case of only minimal faults, price reduction can be asked for.