Japanese phrase
___なら参加できます。 ___ na ra san ka de ki ma su
Meaning
I can join if ___.
When to use it
Says that attendance is possible under a condition. This polite wording sets a limit while leaving the arrangement open.
Example dialogue
土曜日なら参加できます。 do yō bi na ra san ka de ki ma su
I can join if it is Saturday.
じゃあ、土曜日にしましょう。 jā do yō hi ni shi ma shō
Then let's do Saturday.