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? I'm at your service, sir. What can I do for you? If you need anything during your stay, our staff is at your service.

at your service

set phrase

1. Available to help you with whatever you need. One math tutor, at your service! I'm totally at your service—just tell me what you need me to do. Here I am, resident file clerk at your service! How can help with this project?

2. Said upon meeting someone for the first time as a polite way of identifying oneself. A: "Is there a John Jones here?" B: "At your service, sir." Liz Smith, event planner extraordinaire, at your service! Pleased to meet you. Tom Jones, at your service.