Hi Anandhan,
How did you generate the error message ealier? there might be some context node which is having the telepone number field right? if you dont find direct entity which is having telephone field still you can get it from the main context node BUILHEADER context node.
You need to naigate from BUILHEADER context node to corresponding telephone number field context node.
Hopefully telephone field has been taken from the context node BuilStandardAddress context node.
You have to use BOL coding to get the entered telephone id from the BUilHeader context node.
You can check the link between buiheader and builstandarddress context nodes in GENIL_MODEL_BROWSER and give component name BP then click display.
You can find the relations as shown on below, scroll down till BuilStandardAddressRel relation.
