Final answer:
Add a comma and the conjunction 'but' after 'dogs' to connect the two independent clauses correctly in the sentence.
Step-by-step explanation:
The sentence in question requires a change to correct the punctuation. The correct approach is to add a comma and the coordinating conjunction "but" after dogs, as there are two independent clauses in the sentence. The first clause is 'My aunt Debra owns three dogs,' and the second clause is 'she wants to get another one.' Without connecting these clauses appropriately, the sentence results in a run-on. Therefore, the sentence should be changed to: 'My aunt Debra owns three dogs, but she wants to get another one.' The use of a comma before the conjunction in a compound sentence is necessary to separate the clauses and clarify the meaning.