how do you handle it if you turn out to be wrong on a code issue with an associate who was correct?

i am usually the first to admit if i am wrong..

i am asking becasue i have to find a tactful way of going back on what i have said...

i enjoy a good discussion about the code and feel that two professionals should be able to agree to disagree but some people really get mad if they are wrong and they really beleive they are right!