Hi again,
If this is a list form, please try this
1) File > Publish > Export Source Files. Close InfoPath
2) Go to folder where Source Files are saved, open Manifest.xsf in Notepad++. Find all instances of the URL and replace them with the new URL. If you have secondary data connections, update those also.
Save the manifest.xsf file and close. Now right click on the manifest.xsf and select Design to open it back up in InfoPath. Click on File >Publish and verify the URL is correct in the “Publish form to a SharePoint List” section”.
Thanks,
Reema