# Undefine a byte

```
 Action    name: MakeUnknown
 
```

This command deletes the current instruction or data, converting it to 'unexplored' bytes. IDA will delete the subsequent instructions if there are no more references to them (functions are never deleted).

If you have selected a range using the [anchor](https://docs.hex-rays.com/8.5/user-guide/disassembler/navigation/anchor), all the bytes in this range will be converted into 'unexplored' bytes. In this case, IDA will not delete any other instructions even if there are no references to them after the deletion.

See also [Edit](https://github.com/HexRaysSA/docs/blob/8.5/user-guide/user-interface/menu-bar/edit/edit.md) submenu


---

# Agent Instructions: 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:

```
GET https://docs.hex-rays.com/8.5/user-guide/user-interface/menu-bar/edit/undefine-a-byte.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
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.