Cleft lip and/or cleft palate are the most common craniofacial congenital disability, with an estimated 2 affected babies born per thousand in Thailand. Chiang Mai University Craniofacial (CMU CF) center plays a role as the one-stop service providing this type of healthcare. This center serves as the coordinator between hospitals in the treatment network and patients. This research aims to reduce the delays throughout the patients’ treatment plan of the case study hospital as one of the hospitals in this network. Starting with problem identification, two treatment steps, including hearing testing (ABR/OAE) and Cheiloplasty, were 80% of the total delay from the data collection. Then, Root-cause analysis was conducted by interviewing specialists and studying patients’ documents. The main cause of delays was that the patients needed to be transferred from rural hospitals in the area to the hospital that is the subject of our case study. The supporting operations that help in serving patients need co-working operations between the case study hospital and the CMU CF center. Supporting operations including 4 parts were studied and improved based on the Lean concept. Standard procedures were set up when non-value-added activities were eliminated, and value-added activities were improved by IT solution implementation. Finally, when the supporting operations were performed via an IT solution, the processing time can be reduced. Moreover, the implementation of an IT solution helps in tracking and monitoring patients’ status – this advantage leads to a reduction in the number of delayed patients and a reduced delay time in the treatment plan.