Advice - How to tactfully decline changes to a commission.

[quartzzpup.livejournal.com]

I wanted to get some advice on how to deal with this as professionally as possible.

In my TOS I have stated that I will make any changes the commissioner requires that are based around a character's design (colours, accessories etc.) but I have the right to refuse changes that I feel impact on the artistic quality of the work. My problem is that I have never encountered a situation where I have had to enforce this.

Recently I have had certain commissioners ask that I change things such as the colours I have chosen to shade with, or make anatomic changes that impact on my style as an artist. I need to know how to decline these changes if I don't want to make them and what to do if a commissioner becomes confrontational about my choice.

Thank you in advance!