In my previous question What Attributes does a Flesh Form Inhabitating Spirit Ally have? the answer was that the SA would "inherit" so to speak, the vessel's memories, attributes and skills and that it could be improved with -wares an exercise if its magician would choose to, with this idea I let my player do all of that but now he wants to improve his SA skills, at first I said no because it would fall within the effects of the Ritual of Change but reading the rule it speaks specificly about increesing the force of the spirit. which in a normal spirit would increse its skills and atributes but an inhabting spirit would not be like that, skills and attributes would be the vessel's not the spirit's so that got me thinking,
How would that work?
An inhabiting spirit would use any skill (the vessel's and the spirit's) at its force in ranks but with the vessels's atributes?
Does the vessels skills must be improved independantly from the spirit's? if not so, should he had recalculated all the SA's skill to equal ranks with force?