507. What acts amount to waiver.

A subsisting tenancy is recognised, and, if the landlord has notice of the cause of forfeiture, the forfeiture is waived:

(1)     by his bringing a claim1 for, or by the mere receipt of, rent which has accrued due since the cause of forfeiture2, whether the forfeiture is for condition broken or under an express proviso for re-entry3;

(2)     by agreeing to grant a new lease to commence from the regular determination of the existing lease4.

Merely entering into and continuing 'without prejudice' negotiations does not necessarily constitute a waiver5.

A demand made by the landlord or his agent with knowledge of the breach