According to the official XRPL documentation, you can remove a trust line and recover your deposit when the following conditions are met:
- The reserve balance for the trust line must be 0.
- The account’s parameters (flags) must be at default values.
Fireblocks automatically creates trust lines using default flags when you use the tokenization engine or request to add an XRPL asset to your workspace. Therefore, if the asset wallet's reserve balance falls below the minimum 2 XRP for each trust line, the trust line is automatically deleted on-chain. XRPL requires a minimum balance of 10 XRP to maintain an account independent of any trust lines.
Once a trust line is deleted, its reserve requirement is removed. Trust lines can be added back to an account at any time.