Hi sharathbabuYeramalla,
The column titles are set via an XSL transformation in the OTK Client DB Get encap. This policy is read only in OTK 4.x+. Though there is an extension policy for customization it is included prior to the XSL transform so it cannot be altered.
If you would like the ability to customize these column titles I would recommend opening an idea here on communities.
Regards,
Joe