Fix what can be modified via ReadWriteLogRecord

CHANGELOG.md

@@ -15,6 +15,9 @@ release.
 
 ### Logs
 
+- Fix what can be modified via `ReadWriteLogRecord`.
+  ([#3907](https://github.com/open-telemetry/opentelemetry-specification/pull/3907))
+
 ### Events
 
 ### Resource

specification/logs/sdk.md

@@ -154,11 +154,20 @@ value type.
 
 ### ReadWriteLogRecord
 
-A function receiving this as an argument MUST be able to write to the
-full [LogRecord](data-model.md#log-and-event-record-definition) and additionally MUST be able to retrieve all
-information
-that was added to the `LogRecord` (as with
-[ReadableLogRecord](#readablelogrecord)).
+ReadWriteLogRecord is a superset of [ReadableLogRecord](#readablelogrecord).
+
+A function receiving this as an argument MUST additionally be able to modify
+the following information added to the [LogRecord](data-model.md#log-and-event-record-definition):
+
+* `Timestamp`
+* `ObservedTimestamp`
+* `SeverityText`
+* `SeverityNumber`
+* `Body`
+* `Attributes` (addition, modification, removal)
+* `TraceId`
+* `SpanId`
+* `TraceFlags`
 
 ## LogRecord Limits