Delaware Code Title 25. Property § 5502. Landlord remedies for failure to pay rent

(a) A landlord or the landlord's agent may, any time after rent is due, including the time period between the date the rent is due and the date under this Code when late fees may be imposed, demand payment thereof and notify the tenant in writing that unless payment is made within a time mentioned in such notice, to be not less than 5 days after the date notice was given or sent, the rental agreement shall be terminated.  If the tenant remains in default, the landlord may thereafter bring an action for summary possession of the dwelling unit or any other proper proceeding, action or suit for possession.

(b) A landlord or the landlord's agent may bring an action for rent alone at any time after the landlord has demanded payment of past-due rent and has notified the tenant of the landlord's intention to bring such an action.  This action may include late charges, which have accrued as additional rent.

(c) If a tenant pays all rent due before the landlord has initiated an action against the tenant and the landlord accepts such payment without a written reservation of rights, the landlord may not then initiate an action for summary possession or for failure to pay rent.

(d) If a tenant pays all rent due after the landlord has initiated an action for nonpayment or late payment of rent against the tenant and the landlord accepts such payment without a written reservation of rights, then the landlord may not maintain that action for past due rent.