The party having a potential limitation defence may forfeit it either because he has waived such defence by an unequivocal declaration or conduct or because he has admitted his liability. He may be deprived of such defence because taking it would be absolutely incompatible with his behaviour. For example where an alleged debtor promises a payment on account [1].
Neither waiver nor acknowledgement can be presumed, the burden of proof resting on the party pleading the waiver or acknowledgement.
Acknowledgement or waiver may only be made by the party who is potentially liable in respect of the right in dispute.
[1] Cass. 28.I.1993 n. 1051 has so decided but made also clear that a partial payment effected before the expiry of the "prescrizione" does not per se prevent the debtor from raising such defence with regard to the balance getting due after the lapse of the limitation period. The waiver may amount to a remission of debt as codified under Art. 1236 It. Civil Code or can be tacitly implied from the return of the title from the creditor to the debtor (Art. 1237 It. Civil Code).
