fgastone: Level 1 exotics cannot be reconfigured. To craft the weapon with a higher score, you will first need crafting components (including exotic components) and another exotic weapon called Merciless with Gear Score of at least 250. You will also have to buy a Ruthless conversion blueprint, available with vendors from the early stage of the game. After you have this weapon, you'll need to use the Ruthless conversion blueprint to turn the score 250 Merciless into a 250 Ruthless. Afterward, when all appropriate conditions are fulfilled, you may use the Ruthless upgrade blueprint to turn the GS 250 Ruthless into a GS 500 Ruthless (crafting bench must be fully upgraded).
The same process will is needed for the lullaby, but you will need crafting components and another exotic weapon called "Sweet Dream" with a Gear Score of at least 250. If you have any questions, please let us know.