What should i do if my stack overflow query is not getting answers?

I posted as some question at stack overflow . I need some help regarding those queries but I don't know stack overflow working. I post question then waiting for answer of long time . Is there any way to refresh my query again or re-ask same question again? I think there should be re-ask button so that questions will get better response

I don't want type again same question. Please help for this post "How can edit pdf file in android by coding"