Hi Ratnavel,
One of the options you have there is to use the tooling that's specifically meant for this job: https://github.com/eschabell/jbpmmigration.
But I must admit right away: this is work in progress, and if you're looking to migrate very soon it probably isn't sufficient yet. We're working hard to get it there, but we only have so much spare time... ;)
Eric and I are very much interested in your use case, of course, since we're trying to make this tooling as useful as possible. So if you have any questions, scenarios you need support for, or anything else regarding the migration, don't hesitate to contact us!
Best regards,
Maurice