There are two main ways:
A) If the movement coordinates (Start and End) are always the same:
Set X to: Self.X + 50 + 100*[(Self.X-Start.X) / (Target.X-Start.X)][/code:34ho81xw]
(replace 100 by the number that should be added extra when the Sprite almost reached the target)
[i][(Self.X-Start.X) / (Target.X-Start.X)][/i] calculates the movement progress of the Sprite (0 at the beginning, 1 at the end) and multiplies it with [i]100[/i].
That way, the extra value gets higher, the more the Sprite has moved.
Again, this only works [i]if the Start and End values are known and set each time[/i].
B) Use a plugin, for example [url=https://www.scirra.com/forum/behavior-litetween_t70700]LiteTween[/url].