6c37871c__11_CCP_Installment_Agreements__If_the_reason_box_states_
[And ...] IA is defaulted [Then ...] Follow Default procedures. IRM 5.4.11.7, Default and Termination Procedures Provide updated information to IAT administrator. [If the reason box states:] 
Default Ltr Sent Previously, 90 Day Period Expired
Internal Revenue Manual - 5.4.11 CCP Installment Agreements