Changing First extent size by updating systables

This I would like to know more about My understanding is that the extent relates to physical contiguous space on disk or in other words the actual positioning of data on the disk. As this data is currently stored in extents it would seem logical that at some point the data would have to be unloaded and then deleted. Afterwards it should be loaded back into a bigger space I can't see at this moment how changing the index will do this. It may well re-build the index in a bigger space but the actual data I don't think so. Perhaps what is being reported is the current size for the data held plus the size of the disk space for the index divided by some algorithum The index having been created in a bigger space may give the illusion of a bigger first extent but as the whether all the data is now contiguous I'm not so sure -- Terry Boyland