Best way to let a server workflow run async

Hello,

I'm working on a client workflow that, throughout its run, trigger a server workflow. At the moment the client workflows wait till the server workflow is completed, but to work properly the client workflow doesn't need to do this. The server workflow takes a long time to run so now the person running the client workflow is waiting a long time for the server workflow to finish. Is there a way to run the server workflow in async from the client workflow?