There is no automatic way to change the integration from InfoPath to Smartforms. We're doing the same thing and rebuilding with a new process. If you tried to rip out the InfoPath integration (which I'm not sure you can actually do) I'm sure you'd end up with more problems than starting from scratch.
With that said most of the business logic and non client event activities should be more or less the same in a smartforms integrated process.
Regards,
Tim
Thanks for you reply. yes we will create new process and intergrate Smartforms in it.