Article 76 of Civil Code

1 - If neither agreement nor custom specifies a time for exercising the option to withdraw, this option shall remain until the contracting party does something indicating his wish to confirm the subsistence of the contract. 2 - However, if either contracting party refrains from performing his obligations within the specified period, or delays doing so for longer than is customary, the other contracting party may consider this a withdrawal from the contract by that party.