> ## Documentation Index
> Fetch the complete documentation index at: https://tech.ramses.xyz/llms.txt
> Use this file to discover all available pages before exploring further.

# Decrease Liquidity

See [Setting Up Your Contract](./setting-up-your-contract) for the base contract. This example assumes the contract already has custody of the NFT.

* In production, `amount0Min` and `amount1Min` should be set for slippage protection.

## Decrease Liquidity

```solidity theme={null}
    /// @notice A function that decreases the current liquidity by half. An example to show how to call the `decreaseLiquidity` function defined in periphery.
    /// @param tokenId The id of the erc721 token
    /// @return amount0 The amount received back in token0
    /// @return amount1 The amount returned back in token1
    function decreaseLiquidityInHalf(uint256 tokenId) external returns (uint256 amount0, uint256 amount1) {
        // caller must be the owner of the NFT
        require(msg.sender == deposits[tokenId].owner, 'Not the owner');
        // get liquidity data for tokenId
        uint128 liquidity = deposits[tokenId].liquidity;
        uint128 halfLiquidity = liquidity / 2;

        IRamsesV3PositionManager.DecreaseLiquidityParams memory params =
            IRamsesV3PositionManager.DecreaseLiquidityParams({
                tokenId: tokenId,
                liquidity: halfLiquidity,
                amount0Min: 0,
                amount1Min: 0,
                deadline: block.timestamp
            });

        nonfungiblePositionManager.decreaseLiquidity(params);

        (amount0, amount1) = nonfungiblePositionManager.collect(
            IRamsesV3PositionManager.CollectParams({
                tokenId: tokenId,
                recipient: address(this),
                amount0Max: type(uint128).max,
                amount1Max: type(uint128).max
            })
        );

        //send liquidity back to owner
        _sendToOwner(tokenId, amount0, amount1);
    }
```