Metaphors and Spectres

Wondering how common it is to change the name of a book.  Choice of title The Rift results in competing with a number of books called The Rift. The publisher I used apparently didn’t have an interest in pointing out that there were so many identical titles out there.  Am leaning toward making the change but not in a hurry to do so. Ideas that pop in my head is the metaphoric figure of the Old Man who seems remarkable similar to the metaphoric Uncle Sam and the two Teutonic Knights who are transformed from living persons to spectral figures who move through time watching over the Von Mecklenburg family.  At the moment don’t see any legal barriers but no certain nor do I see the negatives surrounding such a change.