> For the complete documentation index, see [llms.txt](https://kb.logicerp.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://kb.logicerp.com/logic-erp-learning-hub-tutorials-and-best-practices/setups/configurations/sale-voucher-configuration/other-settings-1/do-not-allow-modification-of-retrieved-challan.md).
# Do not allow Modification of Retrieved Challan
**YouTube:** [How to Restrict Modification of Retrieved Sale Challans?](https://www.youtube.com/watch?v=SV1TT43u7po\&t=12s)
## How to Restrict Modification of Retrieved Sale Challans?
In this tutorial, we will learn how to **restrict the modification of a retrieved Sale Challan** in Logic ERP. This setting ensures data consistency by preventing edits to challans already used in billing.
***
### **Access Sale Voucher Configuration**
* Navigate to **Sale Voucher Configuration** in Logic ERP.
* Select the **relevant Challan Series** for which you want to enable this feature.
* Locate the option labeled as: **“Do not allow Modification of Retrieved Challan”**
* **Keep this feature disabled** initially to observe the default behavior.
***
### Implement Feature as Disabled
* Create and **save a Sale Challan**.
* Open the **Sale Bill** window.
* Use the **Retrieve Challan** option and select the item to retrieve into the bill.
* Save the **Sale Bill**.
Now go back to the **Sale Challan** window.
* Attempt to **modify the same challan** (e.g., change the quantity).
* Save the challan.
Since the restriction was **disabled**, the system **allows modifications** even after the challan has been retrieved in the bill.
***
### Implement Feature as Enabled
* Return to **Sale Voucher Configuration**.
* **Enable** the option:
> **"Do not allow modification of Retrieve Challan"**
* Save the settings and restart the software if needed.
* Again, try to modify the same Sale Challan that was retrieved in the bill.
* Change the quantity and attempt to save.
This time, the system will **prevent the modification** and show an error message:
> **"This Challan has already been retrieved in a Sale Bill. Modification is not allowed."**
***
### Summary
| Setting | Behavior |
| ---------- | ------------------------------------------------- |
| ❌ Disabled | Allows modifying retrieved challans |
| ✅ Enabled | Prevents editing challans already used in billing |
This feature is crucial for ensuring data integrity between your **challans and sale bills**.
---
# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.
## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.
Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter:
```
GET https://kb.logicerp.com/logic-erp-learning-hub-tutorials-and-best-practices/setups/configurations/sale-voucher-configuration/other-settings-1/do-not-allow-modification-of-retrieved-challan.md?ask=&goal=
```
`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.
Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.