Initiate a call when the user is already on one

Hello, I am trying to initiate a call when a user has someone on a call currently. In the user interface, if someone makes a call when someone is already on a call - Dialpad places the current caller on hold and lets the user initiate another call. When I try to replicate that functionality with the Dialpad API I get the following error message - "User is currently on a call". It is possible to have multiple simultaneous calls in the user interface but I can't replicate this functionality with the API. Has anyone found a work around for this problem?