Write down before changed anything old settings of tftp ip and call manager ip, extension, name or take photo of screen
Cisco 7962 to change tftp
Step 1 Choose SETTINGS
Step 2 Scroll down and Select Network Configuration
Step 3 Select IPV4 Configuration (if have)
Step 4 Scroll to TFTP Server 1 (there will be lock on top of the right corner)
Step 5 Enter **# to unlock (Settings unlocked)
Step 6 Edit TFTP Server 1: field, enter the IP address of TFTP Server (mostly Call Manager ip address 10.92.253.23)
Step 7 Edit TFTP Server 2: field, enter the IP address of TFTP Server
Step 8 Validate to save the entry
it will reload or reboot the phone and check correct extension and name on the screen.
if you can not see lock key at settings, reboot the phone or unplug the phone when you see configuring or configuring vlan press Setting and if you see lock at the corner press **# to unlock and change tftp ip address.