Can you provide more detail please? You mention your changing to OAuth...what version? What was it originally?
You mention "reset based apis". What does this mean? I never hears this term before.
You mention "form based". Are you thinking about the "form data" radio button in Postman? If you want to do an equivalent request in ReadyAPI!, change the MediaType combo box and edit it to application/x-www-urlencoded, this will alter your Content-Type header in your request accordingly.
if this helped answer the post, could you please mark it as 'solved'? Also if you consider whether the title of your post is relevant? Perhaps if the post is solved, it might make sense to update the Subject header field of the post to something more descriptive? This will help people when searching for problems. Ta