Sounds like you need to remove the spool, look at the image.
See those 2 tabs? They are holding the spool on, you have to gently pull both toward the hub with one hand and use the other to push against the hub while pulling the spool outward.
get that off and you'll see a cork disc assembly, look for obvious signs of corrosion. If you can't see any it's probably just the tension knob stuck. I would take mine apart but would rather not at the moment. I've had a few of them and still have the one in the image.
Just checked and mine was rather stuck, not bad but it required more than light torque to turn it free. They turn clockwise, if the reel was left with the drag engaged that means it will only turn counter clockwise.
Look at the back side. At the center oof the drag knob you see a hub with the Vortex logo on it. If the hub is sticking up and you canfeel it protruding above the knob, the drag is engaged and so can only turn counter clockwise which will loosen it.
If the knob and hub are flush with one another the drag is completely disengaged and will turn clockwise, you may have to turn hard. Avoid using tools for this because you'll scar the knob.
