If you have changed the time on your Cisco desk phone following the instructions in this link and the time is still not correct then please login to the Cisco web utility on the phone by following the instructions below to check the regional time zone settings:
1. Press the Setup button as shown below in red:
2. Get the IP address from the phone - to see how to do this please click here.
3. Enter the IP address into a web browser such as Google Chrome
4. This will take you to the Cisco Web Utility interface.
5. Click on the Admin Login in the top right-hand corner
6. Click on the 'Advanced' link in the top right-hand corner
7. Click on the Regional tab
8. Look at the Time Zone settings - please make sure this is set to 'GMT'
9. Please also check the Locale settings - make sure this is changed to en-GB.