それなら
Usage
それなら literally means "if that's the case." それ meaning "that" refers to the speaker's previous statement or the statement which was just mad by the hearer.
Examples
頭が痛いんだけど。それなら、すぐに寝た方がいいよ。
I have an headache. That is why it would be good to sleep soon.
今夜、どこか美味しいレストランで食事したいと思っているんだけど。ああ、それなら、新しく出来た和食レストランに行ってたら?なかなか美味しかったよ。
Tonight, somewhere I planned to go to eat at a delicious restaurant. Aa if that's the case you have to try the new Japanese themed restaurant. It is very delicious.