How can I change PDF format which has JavaScript embedded in it? or Is there a way to change PDF form

Yo! Manual tweaking might be unavoidable here. Most converters strip JS for "security reasons" (eyeroll).

For change pdf format which has javascript, try saving as PDF/A first, then reconverting. Weirdly, that sometimes keeps the scripts intact.

Also, check out PDFescape—it’s online and free, but test it on a small file first.