local ReplicatedStorage = game:GetService("ReplicatedStorage")
local ChangeSkin = ReplicatedStorage:WaitForChild("ChangeSkin")

ChangeSkin.OnServerEvent:Connect(function(player, skinName)
    local character = player.Character
    if not character then return end

    local shirt = character:FindFirstChildOfClass("Shirt")
    if shirt then
        if skinName == "Red" then
            shirt.ShirtTemplate = "rbxassetid://YOUR_SHIRT_ID"
        elseif skinName == "Blue" then
            shirt.ShirtTemplate = "rbxassetid://YOUR_SHIRT_ID"
        end
    end
end)