drop someone a line
US /drɑp ˈsʌm.wʌn ə laɪn/
UK /drɑp ˈsʌm.wʌn ə laɪn/
1.
to send someone a letter, email, or message, usually a short one
:
•
Please drop me a line when you arrive at your destination.
•
I'll drop you a line next week to confirm the details.