click to unanchor?

Seeing as it's already answered, I'll just add example's and explain it the best I can.

Did you put your full code here, what is clickDetector referring to? If you posted your full code here, it should be either script.Parent or script.Parent.ClickDetector unless you made a variable referring to it.

Here's a example:

local clickDetector = Instance.new("ClickDetector",script.Parent)

Like TheDeadlyPanther said, if you use the if statement, you have to use == not =. And like TheAlphaStigma said, LocalScript's only replicate to the client, and do not work server-sided (unless put into the Players' Character).

You could also replace if debounce == false then to if not debounce then

Example:

local debounce = false

if not debounce then
    print("I like cows.")
end

You can replace the function onclicked() and clickDetector.MouseClick:connect(onMouseClick) to clickDetector.MouseClick:connect(function() print("I like cows") end) to make it some-what shorter.

Example:

local clickDetector = Instance.new("ClickDetector",script.Parent)

clickDetector.MouseClick:connect(function()
    print("I like cows")
end)

Final script:

local clickDetector = Instance.new("ClickDetector",script.Parent)

clickDetector.MouseClick:connect(function()
    script.Parent.Part.Anchored = false
end)

If you want it to unanchor everything in a model.

local clickDetector = Instance.new("ClickDetector",script.Parent)

clickDetector.MouseClick:connect(function()
    for _,v in pairs(game.Workspace.Model:GetChildren()) do
        if v:IsA("BasePart") then
            v.Anchored = false
        end
    end
end)

local debounce = false
clickDetector.MouseClick:connect(function()
    if debounce then return end
    debounce = true
    script.Parent.Anchored=false
    --optional,  add a wait() to make debounce = false
end)

Your problem:

When seeing if something is equal to another, you use == instead of =.