2 USC 95b - Transfers of amounts appropriated for House

(a) Transfers among categories of allowances and expenses 
Amounts appropriated for any fiscal year for the House of Representatives under the heading allowances and expenses may be transferred among the various categories of allowances and expenses under such heading, effective upon the expiration of the 21-day period (or such alternative period that may be imposed by the Committee on Appropriations of the House of Representatives) which begins on the date such Committee has been notified of the transfer.
(b) Transfers among offices and activities 
Amounts appropriated for any fiscal year for the House of Representatives under the heading salaries, officers and employees may be transferred among the various offices and activities under such heading, effective upon the expiration of the 21-day period (or such alternative period that may be imposed by the Committee on Appropriations of the House of Representatives) which begins on the date such Committee has been notified of the transfer.
(c) Transfers among various appropriations headings 

(1) Amounts appropriated for any fiscal year for the House of Representatives under the headings specified in paragraph (2) may be transferred among such headings, effective upon the expiration of the 21-day period (or such alternative period that may be imposed by the Committee on Appropriations of the House of Representatives) which begins on the date such Committee has been notified of the transfer.
(2) The headings referred to in paragraph (1) are house leadership offices, members clerk hire, committee employees, standing committees, special and select, house information systems, allowances and expenses, official mail costs, and salaries, officers and employees.