HI Ashik,
In our system, on change of telephone number , it get updated in ADR2 and BUT051.
In ADR2, it will update telephone number at main account level and contact person level .
but in case of email id it will update ADR6 table only at main account level.
so if ADR2 update at contact person address number, why ADR6 does not update at contact person address.
if this is standard. how can we achieve this by custom 
code.