Question: I think I am writing my novel in limited third person but the problem is that there is one part in the story that my main character cannot witness. Is it possible to switch the point of view at one point of the story? I have read books in which this switch creates a pattern throughout the story though I prefer that this only happen once in my novel. What is the best route to go? Should I alternate or is there another way? Thank you!
You can certainly find plenty of books where what you are suggesting occurs.
An obvious example: Harry Potter and the Philosopher's Stone
, which is told entirely from Harry's POV except for the first chapter (where Vernon Dursley and Dumbledore's points of view are used). As I recall, at least two other books in the series start out in a different POV as well.
It's actually fairly common to have a prologue written in another character's point of view that describes events that take place before the main character enters the story - and sometimes before the main character is born.
The value of this technique is that it lets you create dramatic irony - in which the reader knows something the main character does not.
Of course, you can bring your second POV character into the story more often, giving this character his/her own story arc, so that you are telling the overall story from multiple points of view, but it's not necessary.
Also, you shouldn't use multiple points of view unless you have a good reason, because sticking with one POV is usually more satisfying than switching.