Hi, not sure why anyone would want to! can't the tyre be repaired? and to answer your Q yes it is safe to fit an inner tube to a tubeless tyre on a tubeless type rim but you loose the benefit of the tubeless tyre being able to get a puncture, caused by a nail for example, because there's no inner-tube to rupture causing a blow-out. What anyone must NOT do is fit a tubeless tyre to a wheel designed to accept only tube type tyres. hope that's some help.
Ted
March 2011