Section 278(2)(a) in The Bombay Provincial Municipal Corporations Act, 1949
(a)If at any time it appears to the Commissioner, the Standing Committee or the Corporation, as the case may be, that an improvement can be made in any part of the scheme, the Corporation may alter the scheme for the purpose of making such improvement and thereupon the Commissioner shall, subject to the provisions contained in the next two clauses of this sub-section, forthwith proceed to execute the scheme as altered.