Following technote’s  suggestion was’nt work corrently on my Portal Servers. So I have prapered new procedure for me .

http://www-01.ibm.com/support/docview.wss?rs=688&context=SSHRKX&context=SS3JLV&context=SS3NNG&context=SSYJ99&context=SSRUWN&context=SS6JVW&q1=hostname+change&uid=swg21390600&loc=en_US&cs=utf-8&lang=en

http://www-01.ibm.com/support/docview.wss?uid=swg21304780

My configuration:

For Websphere Administrative Console Machine:

1- Stop dmgr ,nodes,instances processes. Change hostname on server

2-Modify   hostnames with new hostname  in  <dmgrprofile>/config/../dmgrnode/serverindex.xml and virtualhost.xml

3- Modify com.ibm.ws.scripting.host parameter  in wsadmin.properties on <profileroot>/properties  both servers (dmgr and nodes)

4- Clean  under dmgrprofile and nodeprofiles temp,wstemp folders.

5-  Start dmgr.

6-Sync nodes with synNode command and start nodes.

For Node  Machines:

1- Stop nodes,instances processes. Change hostname on node servers

2-Modify   hostnames with new hostname  in  <dmgrprofile>/config/…/node/serverindex.xml

3- Modify com.ibm.ws.scripting.host parameter  in wsadmin.properties on <profileroot>/properties  both servers (dmgr and nodes)

4- Clean  under nodeprofiles temp,wstemp folders.

5-Sync nodes with synNode command and start nodes.

6-Star node

7- Download file at following link http://www-01.ibm.com/support/docview.wss?uid=swg21304780 . Extract it into your /ConfigeEngine

8- run following script : ./ConfigEngine .sh localize-clone

9- Verify that the /ConfigEngine/properties/wkplc.properties has been updated with the new hostname.