Change page status, but not the title
So you have setup a nice flat plan and every page has a title corresponding to its contents. Great!
Now, if some pages changes because, lets say, you've finished the layout, you want to update their status in the page plan. Nothing easier than that. Just select the relevant pages in your projects flat plan, switch to the page info by clicking on the document symbol on the right (and thus hiding the messages) and choose "layout done" from the Phase drop down menu on the right. But don't hit "save" yet!
In the title field at the top of the page info you see the title of the first page you have selected in the flat plan. If you save your changes now, this title wil bee applied to all selected pages! If you have have selected pages with different titles, thats probably not what you want. Instead just delete the content of the title input field, and then hit save.
In short: If the title input field is empty, all page info data except for the title (that's phase, file, and notes) will be applied to the selected pages, so titles will remain as they are.