Decrementing attribute on a roll

I am using the basic character sheet with a list of attributes and a list of abilities. In the commands for one of my abilities, I would like to be able to decrement an attribute. So when they fire their bow their ammunition decrements by one. @{character_name} fires /roll 1d12+5 vs Deflect /roll 1d10+4 damage Ammunition, Piercing, Martial, Ranged 100ft, Two-Handed

This is not usually possible. You can only do this in two ways: The sheet is built to do this, and it happens automaticlly You use a script, for which the creator of the game must have a pro subscription.