Find the relative extrema of the function, if they exist. \[ f(x)=x^{2}-6 x+18 \]

Step 1 ：The function given is \(f(x) = x^{2} - 6x + 18\).

Step 2 ：To find the relative extrema of the function, we first need to find the derivative of the function. The derivative of \(f(x)\) is \(f'(x) = 2x - 6\).

Step 3 ：Next, we set the derivative equal to zero and solve for \(x\) to find the critical points. Solving \(2x - 6 = 0\) gives us \(x = 3\).

Step 4 ：We then substitute \(x = 3\) into the original function to get the corresponding \(y\)-value. Substituting \(x = 3\) into \(f(x) = x^{2} - 6x + 18\) gives us \(y = 9\).

Step 5 ：Therefore, the relative extrema of the function \(f(x) = x^{2} - 6x + 18\) is at the point \(\boxed{(3, 9)}\).