An isolated atom has no way to get rid of the energy other than to emit a photon, so an isolated atom will always decay by emitting a photon.
However if there are other atoms around, for example in a gas, the atoms are frequently colliding with each other. If the excited atom collides with another atom the electronic energy can be converted to kinetic energy. This is known as collisional de-excitation, which is as the name suggests the reverse of collisional excitation. In gases at around atmospheric pressure the collisions are so frequent that most atoms decay and lose energy before they can emit a photon. Indeed, when experimenters are trying to measure electronic spectra in a gas they need to use a very low pressure for precisely this reason.
In a solid the atoms are linked together by the bonds between atoms and molecules, and in this case electronic energy can be converted to vibrational energy. Indeed, as with high pressure gases this process is so efficient that in most cases you can't see photon emission from solids and liquids. It usually takes careful control of the experimental conditions to measure photon emission, though there are exceptions like fluorescence and phosphorescence.
