Step One: Login in into your Client-area(DashBoard) and search for rDNS and Single-click on it.
Step Two: Click on Manage Reverse DNS Tab
Step Three: Click on Add PTR in this section.
In Related Item >> select the Hostname of the server
>>Select the Server hostname from the Drop-Down Menu
>> Insert IP address and at the bottom in RDATA and insert PTRD name and click on Add.
Final Step: Here the PTR record is Updated successfully, You can also Re-Edit the Record or Delete it here.