The correct answer is -repeat the information for the new dose of medication.
In this case you are instructing medication dose adjustment for someone already taking a medication.
Correct usage a medication is paramount. Many patients will agree, or yes "I understand" even though they may not. They are frequently hesitant to ask questions.
What studies have shown is the use of "teach back" eliminates this problem. After situations such as instructing patients regarding changes, having them teach back to you what they heard, eliminates the possibility of them understanding correctly