Methods and apparatus directed to utilizing an automated messaging system to engage in a dialog with at least one user, via a computing device of the user, to determine a particular service entity for an action. In some implementations, the automated messaging system may generate a plurality of questions and/or other prompts to solicit user interface input from the user(s) for use in determining the particular service entity and/or in determining one or more criteria for the action. Some implementations are further directed to performing one or more computing actions based on the determined service entity and optionally based on one or more criteria for the action determined via user interface input of the dialog.