If you have installed Microsoft 365 on the maximum number of PCs, Macs, or tablets and want to use Microsoft 365 on a different device, you can deactivate a device by visiting accounts.microsoft.com, after which you can install Office on a new device. The copy of Office on the device you deactivated will revert to read-only mode, which means documents can be viewed but not edited. You will not lose any documents that are saved locally on the original device.