For details see https://www.rabbitmq.com/install-debian.html
# Stop RabbitMQ
$ rabbitmqctl stop 
 
#Change /etc/hosts
#Change /etc/hostname
 
#Uninstall old RabbitMQ: 
$ dpkg -P rabbitmq-server
 
#Remove RabbitMQ’s database: 
$ rm -rf /var/lib/rabbitmq
 
#Find erlang’s process that is running rabbit: ps ax | grep rabbit
#Kill the listed process
 
#Reinstall RabbitMQ: 
$ apt-get install rabbitmq-server