No one has all the answers

 A good leader will acknowledge that they do not know the answer to a question. It's okay to admit this and it's okay to be vulnerable! None of us are expected to know everything all of the time. In addition, a leader won't drop the ball and leave the question unanswered. It's wise to always play to one's strengths as well as admit one's weaknesses. Believe it or not, this truly earns you respect in the end for being so very forthcoming.

It's okay to say "I do not know but that is a wonderful question". You can give the promise to go find the answer for the person who was asking and so by doing that, we all learn together. Part of being helpful isn't always about knowing the answer but learning how to go find it, relying on resources whether they be forum posts, links, or other knowledgeable people.

At times you won’t know the answer yourself but you will know who can give the person the right answer. In such a case, feel free to send the person asking the question to the right person. 

step content provided by @SparkyGizmo