Once you have the Sebilis Slave Mine Map you can click a rock at -191, -113, 403 in the Reet Slave Mine and it will send you to the solo Reet Resistance Cave.
Clicking the rock will take you into a solo instance and you will not be able to take your team with you. You must disband from your group or it will not let you zone into the instance.
Just keep heading in to the mines to find the rock. At the tunnel that splits left and right, left goes to spore king, right goes to your rock. Hug the left wall and you will see it. It is in a large room roughly underneath the slave quarters in the mines. The rock is on the left as you enter the room from the area with the mushroom and dog mobs.
Inside the instance examine the Ensorcelled Boot to summon the frog from upstairs. Talk to him and he tells you to talk to his leader, Captain Rroop. This completes A Reet's Freedom. Do NOT leave just yet, the quest continues. Captail Rroop takes a scouts report while you're there, listen the the report. After listening to the report you will be asked to kill 12 iksars in the instance.