at (one's) service
Available to help or serve one. Here I am, resident file clerk at your service! How can help with this project?
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
at someone's service
Fig. ready to help someone in any way. The count greeted me warmly and said, "Welcome to my home. Just let me know what you need. I'm at your service." The desk clerk said, "Good morning, madam. I'm at your service."
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.
at (someone's) service
Ready to help or be of use.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.