This is a reply from EG, a few months ago, regarding a color change on a pair of boots:
Thank you for your email.
It would not be possible to change the colour from Burnt pine to Dark oak. We could make them darker but it would not be as dark as the Dark oak calf.
If you would like to go ahead with this, we can arrange for the boots to be collected and returned by DHL. The charge for collection/ repolish and return is £105.