Obviously the voice over artist has no idea what she's doing. The job of the VO artist is first to have a good voice, and second, if he/she claims to be able to produce and deliver the VO, make sure the delivery quality is pristine.
Obviously that's not the case, so you should inform her that the quality is not up to par, and have he redo the VO. Possible problems are a bad connection somewhere in her system, broken or compromised wire from the mic to the computer or sound board, and even problems with the encoding.
If the noise is not there when she's not speaking, there's no way to easily remove the noise by sampling just the noise.