Right indicator not working

@ranadebnath you are not telling us what you have already checked. Since the left side works, your blinker relay and fuse are likely fine. Most common issues for a not working indicator are a burnt-out bulb, a faulty switch, or a loose/pinched wire.

Not sure why you would need to "Replace the voltage regulator rectifier" which really sounds more like a guess to me ;-). Anyhow, you can now download the SM for the FZ6 from this page Yamaha FZ6 under the Documents Header. Page 402 shows you the diagram for the signaling system.