Section 11(2)(b) in The Consumer Protection Act, 1986
(b)any of the opposite parties, where there are more than one, at the time of the institution of the complaint, actually and voluntarily resides, or carries on business or has a branch office, or personally works for gain, provided that in such case either the permission of the District Forum is given, or the opposite parties who do not reside, or carry on business or have a branch office, or personally work for gain, as the case may be, acquiesce in such institution; or