Methods, systems, and apparatus, including computer programs encoded on computer storage media, for determining a transfer option for transferring a call. One of the methods include receiving, by a call assistant engine, a keyword related to information provided by a user to an agent during a call; generating, by the call assistant engine, follow-up questions to be displayed on a user device of the agent in an interactive format, the first follow-up question being generated based on the keyword, each of the following follow-up questions being generated based on an answer of the agent to the previous question; and determining, by the call assistant engine, based on answers of the agent to the follow-up questions, a transfer option for transferring the call.