How to take back purple plots?

Purple plots are owned by other alliances. You can take these back in the same way as occupying an empty plot but using the occupy option, they only difference is that you need to destroy the defence first.

Each occupied plot has a durability of 500 and your attacking formation will have a Destruction power rating. You will need to attack and win (if you can take the plot in the first place then you can win) until the durability is reduced to 0. This will normally mean 2 attacks or more. Once you reduce it to zero you will claim it as yours.

The current owner or any member of their alliance can camp on the plot to add their formation to the defenses.