Using
PedSetActionTree(gPlayer, "/Global/Player", "Act/Anim/Player.act") -- Will change the style
And if you want to add a button to change it do this :
if IsButtonPressed(0, 0) then -- Left Button
PedSetActionTree(gPlayer, "/Global/Player", "Act/Anim/Player.act")
elseif IsButtonPressed(1, 0) then -- Right Button
PedSetActionTree(gPlayer, "/Global/P_Grappler_A", "Act/Anim/P_Grappler_A.act")
If you want add more buttons just remember to use at the first part "elseif" instead of "if"