You can regenerate tasks for a specific task type that has triggers related to tasks or matters. To do this navigate to the task type you wish to regenerate tasks for and select the “Regenerate Tasks” button.

This will bring up a pop-up from which you can select specific clients and matter types to regenerate the tasks for. If none are selected, tasks will regenerate for all matters. 

This process is completed as a background task and the progress can be checked from the Background Operations in the upper right hand of any page.