It is
possible to change a database link password without dropping and recreating a
database link.
The ALTER DATABASE LINK
statement can be used and you do not need to specify the target TNS Service name either.
ALTER DATABASE LINK DB_LINK_NAME connect to USER_NAME
identified by NEW_PASSWORD;
main url: https://jhdba.wordpress.com/2015/02/13/changing-a-database-link-password/
