HOTSPOT
Your network contains two DHCP servers named Server1 and Server2. Server1 fails.
You discover that DHCP clients can no longer receive IP address leases.
You need to ensure that the DHCP clients receive IP addresses immediately.
What should you configure from the View/Edit Failover Relationship settings? To answer, select the appropriate
setting in the answer area.
Hot Area:
Answer: 
Explanation:
A manual failover will have to occur by clicking on the Change to partner down button (the partner has to
actually be unavailable to click this button).
Note: You can manually change the state of a server which is running in communication interrupted to partner
down using DHCP MMC or DHCP PowerShell.
In MMC, go to IPv4->Properties, go to Failover tab, select the specific failover relationship and click edit. You
will see “Change to partner down” button on the edit page. This button is enabled when the server is running in
communication interrupted state.Reference: DHCP Failover Hot-Standby Mode
http://blogs.technet.com/b/teamdhcp/archive/2012/09/03/dhcp-failover-hot-standby-mode.aspx