how to change relay log fie name on "Adding Slaves to a Replication Environment"?

MySQL document advised that "new slave relay log file name " should followed the "old slave relay log file name"

to avoid this problem, use the same value for --relay-log on the new slave that was used on the existing slave

address:http://dev.mysql.com/doc/refman/5.7/en/replication-howto-additionalslaves.html

but what should I do if I want to use a new relay log file name,not the old one

thank you very much ^_^