You would just use the tween service and set the anchor point to the target anchor point
local TweenService = game:GetService("TweenService")
local TargetAnchorPoint =Vector2.new(0.5, 0.5) --TargetAnchorPoint
local SomeUIElement = --put the gui element here
local Tweeninfo = TweenInfo.new(1) --adjust to your liking
TweenService:Create(SomeUIElement, Tweeninfo, {AnchorPoint = TargetAnchorPoint}):Play()