Table 6.6 – Alterations to Existing Elevators
Current Guidelines:  
4.1.6  Accessible Buildings: Alterations.

(1)  General.  Alterations to existing buildings and facilities shall comply with the following: . . .

(b)  If existing elements, spaces, or common areas are altered, then each such altered element, space, feature, or area shall comply with the applicable provisions of 4.1.1 to 4.1.3 Minimum Requirements (for New Construction). . . .

Final Revised Guidelines:  
206.6.1 Existing Elevators.  Where elements of existing elevators are altered, the same element shall also be altered in all elevators that are programmed to respond to the same hall call control as the altered elevator and shall comply with the requirements of 407 for the altered element.

Model Codes & Standards
IBC 2000:  Section 3408.7.1 has an equivalent requirement for alterations to existing elevators.

IBC 2003:  Section 3409.7.2 has an equivalent requirement for alterations to existing elevators.