I've not had as much of this as I thought I would, however, people have still asked "to be made skinnier" (mostly as a joke) so I thought I'd blog about it.
Editing is a basic correction of images (ie. removing a spot or two, cropping, straightening, and adjusting for exposure, temperature, white balance and contrast, converting to black and white etc). Retouching is a more specialised service and is a manipulation of how an image looks (such as teeth whitening, removing or replacing items, head swaps, face manipulation, changing colours, fixing hair styles etc), and therefore requires a lot more time and expertise which will incur additional fees, generally priced per edited photo.
Below is an edited photo as an example of what I might do for a wedding. See if you can spot the differences!