LETKNOW
let know
Verb
- To inform (someone) (of something).
- I sent an e-mail to let John know what we found.
 - Let me know when you are arriving .
 - "I'm not sure which flight I'll be taking." / "Well, as soon as you find out, let me 'know."''
 - He let her know about his plans.
 - If anyone has seen him, let us know of his whereabouts.
 
 
The above text is a snippet from Wiktionary: let know
and as such is available under the Creative Commons Attribution/Share-Alike License.