Thank you both, I normally write only from the POV of one character in my stories and they don't have a large cast so don't add characters - but I did write one a series with multiple viewponts so I think that was where I must have used this feature.
And thanks, Peter, for the link. which I will check out. A tool like that did something like that would be useful as I often decide to change the day a particlar scene happens, and at the moment I don't think there is a way to change the day of every scene following it except manually (I could be very wrong, though!)