Beneficent Transposition

When an ally that you can see within range would be struck by an attack or fail a saving throw against a damaging effect you may use your reaction to switch places with them, suffering the effects of the attack or failed saving throw in their place. Even if the attack roll would not have hit your AC, for the purposes of this effect damage will be rolled as of the attack was successful. 

If the damaging effect covers an area and both you and the target are within the area there will be no change in the result of your targets saving throw and they will only have switched places with the caster upon completion of the spell.