Changing the name of a property from a model class

I am wanting to change the name of the property that is currently in the model class for certain conditions. I was reading up on how to do this and ran into a possible solution for what I am wanting to do. However, when I do the following with Reflection it says

Object Reference not set to an instance of an object

But in the model class I do have the name. Am I not using this correctly?

Model class:

public class Example1
 {

    public Property1 Property1 {get;set;}
 
 }

public class Property1
{
  public string Fruit {get; set;}
 
}

then I have the following

var firstName = "Car";

Example1 myProperties = new();

SetPropertyValue(myProperties, myProperties.Property1.Fruit, firstName);

....

 public static void SetPropertyValue(object p_object, string p_propertyName, object value)
 {
            PropertyInfo property = p_object.GetType().GetProperty(p_propertyName); // grabs the property name 
            property.SetValue(p_object, Convert.ChangeType(value, property.PropertyType), null);
 }

I do not seem to understand why it is giving me that message if I do have the property name there. Ultimately I am wanting to change the name of the property from Fruit to Car. Any pointers would be appreciated.