Answer: Using an exclamation point or using the words what and how.
Step-by-step explanation:
To change a declarative sentence into an exclamatory sentence you need to change the punctuation. Exclamatory sentences use an exclamatory point (!).
Ex) It looks great. ➜ It looks great!
Next, you may need to put "what" or "how" at the beginning of the sentence. If the original sentence starts with noun, adjective, or an adverb, you will need to use "what" or "how" depending on the context. You may also need to reword the sentence but do not lose the meaning of the original.
Ex) This is a big house. ➜ What a big house this is!
Ex) I loved the book. ➜ How I loved the book!