at someone's disposal
• ready to assist the person concerned in any way they wish.
• "I am at your disposal until Sunday"
at one's disposal
• available for one to use whenever or however one wishes.
• "a helicopter was put at their disposal"
Similar:
for use by,
in reserve for,
in the hands of,
in the possession of,
within the reach of,
within easy reach of,
at someone's fingertips,
