You can say you were diplomatic (adj) and acted diplomaticallydiplomatically (adv)
- diplomatic - employing tact and conciliation especially in situations of stress. e.g. "a diplomatic way to say no"
from the web:
1 - While engineers must be careful not to pass judgment on a particular matter, engineers who are faced with this type of ethical quandary should make every attempt to carefully, delicately, and diplomatically sidestep the matter in order to remove any appearance of an ethical conflict.
2 - Even when Quent explained that Jenny had earlier admitted going outside and chatting with a girlfriend, all Lucy had said was, “No harm done. I know the girl means well.” As diplomatically as possible, Quent had proposed that the children come to live with him ...
3 - In fact (and I don't know how to say this diplomatically), I don't really care whether or not people come to hear me speak anymore.
4 - I'm sure there were other ways I could've handled the situation more diplomatically. But you know what? Maybe not. Sometimes you have to be willing to fight for what's right.