You can change 'Name' by selecting a device from the 'Device list'.
'Name' and 'Assigned name' will be changed.
In the 'Device list', you can see the name you manage by selecting the check box as shown in the picture.
If you turn off the 'allow modification of device' checkbox from 'Restrictions' and check 'keep device name up-to-date with dashboard' with the name change, you can completely manage the device's name as the administrator-specified name.
Multiple device names can be changed using API.
https://documentation.meraki.com/SM/Other_Topics/Renaming_Systems_Manager_Client_Devices_with_a_.csv...