During the last decades, several research works have been conducted in Business Process Management (BPM) field, and a whole range of tools allowing capturing and managing the business process (BP) has been proposed. However, the current BPM systems leave aside the informal work, which is often based on communication and collaborative tools. In this paper, we introduce the concept of "communication-based manual task" in the BP design. It is a kind of a BP activity which is associated to a set of semantic patterns that enable the qualification of communication content as an achievement of the BP task. This association of semantic patterns with BP activities enables the system to capture informal work, done through communication and collaborative tools such as: email, phone calls, instant messaging, etc. We have implemented and applied the proposal to the customer relationship management (CRM) field in order to respond to the challenges induced by the variety of communication channels. We highlight two main advantages compared to classical CRM approaches. It firstly enables the reconstruction of the customer journeys across the communication channels and secondly identifies all BP actors who are involved in the customer journey; providing by this way a mean to promote collaboration between communication channels teams.