Question

در خدمت شما هستم ( وقتی کسی کاریمون داره )

Answer 1

At your service

Answer 2

I'll be there for you!
"I'm at your command!"

Answer 3

We are available ......

At your disposal در خدمت کسی بودن به طریقیکه وی مایل است

At your service در خدمت کسی بودن در صورت نیاز

We are available for any clarifications.
We are at your service for any clarifications.

We are at your disposal for any clarifications.