Most vocal coaches and choir directors will teach a vocalist to face strait ahead and sing. Breathe deep, keep shoulders high, expand the intercostals and sing from the diaphragm. This may be the best way to project a clear and powerful singing voice to an audience, however it is not always the best technique for the recording studio or vocal booth. In the recording world we look for vocal stylists, that can utilize their chest voice, head voice and falsetto.
If you find yourself working with a trained singer whose chest voice is ruining your recording, you may find it difficult to convince them to ignore their training. So don't! Just casually reposition their microphone. The singer's voice will change dramatically, even if they do not realize. Generally, you move opposite the part. If the vocal part is higher than the singer's comfortable register, you move the mic down. If the part is below their comfortable register, you move the mic up. Although, these rules are not set in stone so you can experiment. Let your creative juices flow!