Longsword Master

You have trained in the art of the sword. You  have learned to use your sword to both offend your opponent and defend against their attacks. Like the weapon itself you have made your skills versatile changing tactics with the needs of the situation.

While using a longsword you gain these abilities. 

• While using a Longsword two handed -and no other weapons- gain +2 AC against Melee attacks.
• While using a Longsword two handed -and no other weapons- As a bonus action you may add an additional +2 to your AC against one opponent till the beginning of your next turn.
• While using a Longsword two handed -and no other weapons- your Longsword gains the finesse trait. 
• While using a Longsword two handed -As your item interaction, or a bonus action- you may change the type of damage to Bludgeoning, Piercing, or back to Slashing.
• While using a Longsword one handed gain +1 AC.
• While using a Longsword one handed -as a bonus action you may make an additional Attack  with the pommel of the longsword. This attack does 1d4 (no bonus damage from abilities) bludgeoning damage and makes the target make a dc 6+damage done constitution save or gain disadvantage on the first attack of next round.