For better known to the end-users, here is the demonstration from tripod to monopod of Sirui M-2205,Magic Series.                                                          
First of all, you will find a complete original photo of Sirui M-2205 before it is transformed. Sirui's Magic Series Tripod is distinguished for its magic transformation from tripod to monopod which enables you to have both tripod and monopod 

The original M-2205
 

First loose the Leg-connector

Then the leg can be took off
 
The inside-structure of the Leg-connector
  

Take the Connecting-Plate off from the tripod

And then mount the Connecting-plate onto the single took-off leg 
 

And this is the monopod

Tight this joint hardly to make it more compact

The transformed Monopod

At the end put your ballhead on , and a complete transformer is done 

As you can see , the three parts are in a good connection