8. A non-transitory computer-readable medium storing instructions that are configured to cause one or more processors to: receive, at a task completion service, an input comprising information in a natural language; determine, at a dialog manager of the task completion service, an intent of the input; determine, at the dialog manager, target information to fulfill the intent; identify, at the dialog manager, one or both of information among the target information that is available to the dialog manager or information among the target information that is not available to the dialog manager; generate a conversational understanding document comprising the intent and the identified information; and forward the conversational understanding document to a task completion handler separate from the dialog manager.
9. The non-transitory medium of claim 8 , further storing instructions configured to cause the one or more processors to select, at the task completion handler, missing information from among the identified information, and guide, at the task completion handler, a conversation to request the selected information, wherein the updated information is received by the dialog manager in response to the conversation requesting the selected information.