In case if you have lost agent registration pwd and want to create new one. Go to setup=> registration pwd and remove the existing one.

then in the OMS server execute below command,

/emctl secure setpwd
Oracle Enterprise Manager 11g Release 1 Grid Control 
Copyright (c) 1996, 2010 Oracle Corporation.  All rights reserved.
Enter Enterprise Manager Root Password :
Enter New Agent Registration Password :
Registration Password added successfully.

root password above is sysman password

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