Hi Niraj,
MR as173d is correct. We need some screenshots in order to better understand what is happening.
Until that point we only can guess.
My best guess at this point is that:
- you initialize the variable in service A before invoking service B
- you are dropping the variable inside service B
that would explain why you cannot see it in the pipeline while debugging the service.
Or is your problem happening at design time?
More details would help us help you 
Best regards,
Vlad Turian
#webMethods#Integration-Server-and-ESB