When you change other elements of the Visio template, such as the input control or default value for a template parameter,
applies the changes to existing tasks that use the template.
If you have tasks that already use the Visio template, review the listed tasks after making uploadant changes to the template. If the changes are not compatible with an existing task configuration, the task may fail at run time.
If you want to make signification changes to the Visio template and already have tasks that use the existing template, you might want to upload the template again and configure the changes with the newly-uploaded template.