It has to do with orbital direction. My mission said i needed a longitude of AN of 256.5 but i had 70.4. after experimenting i found out that if i aim retrograde and full throttle it'll reverse. just fire retrograde but don't follow the node. it will seem like you're going for a landing but as long as you keep firing where retrograde was, it'll turn into prograde and back to orbit. after this you should change your angle (if polar then 90 etc) by using normal and antinormal and lastly adjust apoapsis and periapsis. If any more help is needed just ask