Cap. 13 ст. 111Revocation of contract.

(1) Until the contract is complete, both the offer and the acceptance may be revoked. If, however, the person making the offer declares that he will keep it open till a certain time, or if a time is implied by the nature of the contract, the revocation thereof before the lapse of such time will not prevent the completion of the contract.

(2) If the offer empowers, even impliedly, the other party to carry out the contract without previously communicating his acceptance, the contract is complete as soon as its execution has commenced within the customary or prescribed time.