Please let me know if you need me to be more specific. And let me know if you have any questions. please begin with Dear students or Dear curriculum committee at the American University of Sharjah or Dear professor. Depending on who you choose your audience to be.
If the audience is the students, You should address the petition to those who think the syllabus is not perfect. (persuasive, argumentative strategy)
If the audience is the professor, The changes you are suggesting are minor changes like assignments, course organizations, readings, etc.
If your audience is the Curriculum committee, That means the changes suggested are major like requesting substantive changes to the number of essays, weight of each assignment, etc.
You can also compare another syllabus at another university and compare it to this one and suggest changes.
Pick one audience and write a petition letter to them using persuasive and argumentative strategies.