no need to reinstall, few places you need to make the change to:

1. change the host file or dns, then access CM through hostname instead of IP address

File: /etc/hosts

2. make sure the DB hostname is correct if your repo is on the same server:

file: /etc/cloudera-scm-server/db.properties

3. change agent configuration to make sure it using hostname or new IP address

/etc/cloudera-scm-agent/config.ini

restart CM and CM agent.