In most states there is a 3 day notice served upon the tenant delinquent on rent to pay or quit the rental by the landlord. If you were served with some notice to vacate the rental due to failure to pay the rent by the landlord, but you and the landlord reach some understanding on what is owed later after service of the document, that agreement would supersede what was required in the prior written notice.However, with respect to the second agreement, make sure that it is memorialized in writing and signed by you and the landlord to protect your interests.