Project changes are often required. There are three ways to do this. You can simply go Edit mode, make changes to the Project and save them. This is recommended in most cases. If changes are significant and you want to suspend the Project so that others cannot make comments or suggestions, then you can Pause the Project in Edit mode. Finally, if the original Project is incorrect and you do not want others to see the Project at all, you can unpublish the Project in Edit mode.
It's a good idea to let users know what changes you've made after you've made your changes and activated the Project. Go to the Updates tab and enter a brief title and description of the Project change. This will not only memorialize the change, but will send an email to all Project participants, letting them know.