You cannot currently change any EXIF Metadata (camera, aperture, shutter speed, lens, focal length etc) in Capture One.
There is software that will let you change EXIF Data (search for EXIF Editor or use Media Pro's option to write-out-changes to the raw file). It's also possible that Capture One will add such a feature in the future; I'd suggest submitting a support case with your feature request - every such support case is read and logged and that data is very important in the feature planning meetings in Copenhagen.