Yeah, your question was a little bit fuzzy. If I understood correctly, you first check the form then if the fields are correct, you give the possibility to either change the entered information or send it.
Ok, heres a solution when you want to go back to change entered information..
In your first form page you have the fields. Put them like this:
<input type="text" name="field1" value="<?=$_POST['field1'] ?>">
Put all the fields like that. Dont worry, they are not showing anything the first time because the $_POST arrays are empty.
In your check-page, put your forms values in hidden fields inside a form. Heres a little snippet so you dont have to write every variable again.
// get keys and values from $_POST.
foreach($_POST as $key=>$value)
{
echo "<input type='hidden' name='$key' value='$value'>\n"; }
}
Now when you submit that to the first form, they show up in the input fields.