put the part that you want to be respawned into replicated storage in the position you want it to be respawned in (if you want it to appear in different places move its position using PrimaryPart, which will have to be set..)
then use this script inside the respawn button which also has a click detector:
local respawn_button = script.Parent.ClickDetector
local function respawn()
local original = game.workspace:FindFirstChild("model name here")
original:Destroy()
local model = game.ReplicatedStorage:FindFirstChild("model name here"):Clone()
model.Parent = game.workspace
end
respawn_button.MouseButton1Click:connect(respawn)
respawn()
Think this should work but I've just typed it here and didnt test it in studio :P