如不能来请打电话告诉我的英文

if you can't come please ring me up

• 如:    in compliance with ...
• 不能:    cannot; must not; ...
• 来:    come; arrive
• 请:    request; ask
• 打电话:    make a phone call; ...
• 告诉:    tell complain; acc ...
• 我:    I; my; me