Office 365’s Exchange Online has built in functionality that allows you to easily manage your conference room schedule. Once an administrator creates the room as a resource in Office 365 and properly configures it, users can select the room when sending out their meeting invitation. The room’s calendar can automatically accept or decline invitations based on availability and is even able to process cancellations and changes.
Microsoft has an excellent article that walks administrators through creating and managing the room resource here.
Note that you can also use resource to help book equipment.