Reassignment task to principal after Out Of Office.

I have a workflow that uses substitution list to reassing tasks inmediatelly to a second user in the list when the principal turn on the Out Of Office. I want get the tasks are reassigned to the principal user of the list, after the this one turn off the Out Of Office. Are there any way to do with the Workflow Designer?, or what another way I could this?

Thanks for your answers.

Regards.

Diego