Answer:
1. By removing the reflector or reflecting elements
2. By using absorbing material on the reflecting surfaces.
Explanation:
To solve problems caused by reflecting surfaces, you can remove the reflector or reflecting elements. However, sometimes it is enough to turn/move the reflecting element and change the reflections. Furthermore, using absorbing material on the reflecting surface can help reduce comb filtering as well.
In some cases, it is possible to place the sound source so close to the reflecting surface, that there is no suspension between the direct sound and the reflected sound.