در اختیار کسی بودن
It's not at my disposal
تو دست و بال، تو بال و پر، در اختیار
۱ - در اختیار داشتن
able to be used or to help you
available for someone to use for whatever or whenever you want
I don't have any car at my disposal
۲ - در خدمت کسی بودن
If you say that you are at someone's disposal, you mean that you are willing to help them in any way you can.
۲ - در خدمت کسی بودن