Landlords and Tenants in Arizona – A landlord is not required to accept a partial payment of rent or other charges. A landlord accepting a partial payment of rent or other charges retains the right to proceed against a tenant only if the tenant agrees in a contemporaneous writing to the terms and conditions of the partial payment with regard to continuation of the tenancy. The written agreement shall contain a date on which the balance of the rent is due. The landlord may proceed as provided in article 4 of this chapter and in title 12, chapter 8 against a tenant in breach of this agreement or any other breach of the original rental agreement. If the landlord has provided the tenant with a notice of failure to pay rent as specified in section 33-1368, subsection B prior to the completion of the agreement for partial payment, no additional notice under section 33-1368, subsection B is required in case of a breach of the partial payment agreement.
Except as specified in subsection A of this section, acceptance of rent, or any portion thereof, with knowledge of a default by tenant or acceptance of performance by the tenant that varied from the terms of the rental agreement or rules or regulations subsequently adopted by the landlord constitutes a waiver of the right to terminate the rental agreement for that breach.
Source: www.azsos.gov/public_services/…landlord_tenant_act/residential.pdf