Symbols can confirm or clarify themes by using something but it meaning something else that reveal the theme, for example, the theme is kindness is often overshined by greed, the symbol is a caged bird without food in a magic castle trapping a selfish, greedy prince. It is only when the prince gets board of the castle but can't go outside because of the magic spell, and realizes the bird also wants freedom, that the theme shows, or is revealed
In the beginning, Greg dreaded getting a lecture from his father. In the end, he looked forward to the lecture because he knew what to expect.
The narrative implies that Greg was upset and unwilling to listen to his father's admonition.
In the end, we can assume that this changed because Greg was awaiting his father's lecture.
The change was due to his father wanting to tell him about losing his son.
I know this probably isn’t 150 words, but it’s a start.
A teacher. Im not sure you would learn this in English