...
If the host is currently running a service that exists in the template you plan to apply, the service on the host will be updated with new information from the template, including service description, tags, and interface labels. The service name and service type will not be updated.
If the host is not currently running a service that exists in the template, all configurations for that service in the template will be created and added to the host.
If the host is currently running a service that does not exist in the template, the service will be removed from the host when you apply the template.
After applying a template to a host or multiple hosts, you can set the lock type on specific hosts to address various situations. For information, see Setting Lock Type on Hosts.
To create a template, do the following:
...