No official, head of department, deputy or any subordinate shall
be permitted to attend any conference or conventions at the City's
expense without first obtaining the approval and consent of the City
Council and the Board of Estimate and Contract.
At the same time as such person applies for the approval and
consent of the City Council to attend any conference or convention,
he shall submit an estimate of the expense to the City for such attendance
at such conference or convention. No advancement shall be made by
the Comptroller or other financial officer of the City in contemplation
of such expenses.