We try and be really honest and upfront about our concerns with any issue that we may have opposing issues on, whether it is something small like a UX change, or bigger matters like company direction or looking for funding etc.
One critical thing to keep in the back of your mind in situations like this is: “We are all on the same side”. Every stakeholder in the business is looking for the best outcomes, so try and remember this if you ever feel like the other party is ‘attacking’ you – 99% of the time, they are not, but rather they are thinking they are doing what is best for the company.
As well as explaining your point of view, try and back it up with evidence and facts, rather than emotion. A wise man once told me: “If nobody is happy with a final decision, then it is a good compromise”. Be prepared to sacrifice your ego or pride in these cases. Some of my best learning has been from times that I have perceived that I had to ‘back down’ only to find out later that it was the best decision. Trust in your partners that sometimes they may know better than you.