Related Rule
Philippines
Practice relating to Rule 66. Non-Hostile Contacts between the Parties to the Conflict
According to the Report on the Practice of the Philippines, “government troops are directed to negotiate with the rebels in cases of armed confrontation”. 
Report on the Practice of the Philippines, 1997, Chapter 2.2.
The report also notes that, owing to the guerrilla nature of the conflict, negotiations between government troops and the armed opposition are usually carried out through third parties (local political and religious leaders). Cease-fires are, for example, negotiated to prevent economic disturbances or during Christian holiday celebrations. 
Report on the Practice of the Philippines, 1997, Chapter 2.2, referring to Romy Elusfa, CHR Stung by AFP Rejection, Today, 12 April 1997; Ali G. Macabalang and Cena de Guzman, Gov’t, MILF Reach Accord on Dam Dispute, Manila Bulletin, 30 January 1995; Farm Pact Forged with MILF Bared, Manila Bulletin, 10 June 1996; Aris R. Ilagan, AFP Optimistic on Truce with NPA: Holiday Ceasefire on, Manila Bulletin, 25 December 1993.
The Code of Ethics (1991) of the Philippines stresses that the white flag of truce is a “worldwide custom used to signal the temporary cessation of hostilities between warring parties”. 
Philippines, Armed Forces of the Philippines Code of Ethics, 1991, Article 5, Section 2(4.5).