diff --git a/docs/DeveloperGuide.md b/docs/DeveloperGuide.md
index a19fc6f6730..975f5e1af48 100644
--- a/docs/DeveloperGuide.md
+++ b/docs/DeveloperGuide.md
@@ -305,26 +305,18 @@ Why is this implemented this way?
Deletes a `doctor` or `patient` entry by indicating their `Index`.
This command is implemented through the `DeleteCommand` class which extends the `Command` class.
-* Step 1. User enters an `delete` command.
-* Step 2. The `AddressBookParser` will call `parseCommand` on the user's input string and return an instance of `deleteCommandParser`.
-* Step 3. The `parse` command in `deleteCommandParser` calls `ParserUtil` to create instances of objects for each of the fields.
- * If there are any missing fields, a `CommandException` is thrown.
- * If input arguments does not match contraints for the fields, a `IllegalArgumentException` is thrown.
- * If the provided `index` is invalid, a `CommandException` is thrown.
-
-The activity diagram below demonstrates this error handling process in more detail.
-
-
-
-* Step 4. The `parse` command in `deleteCommandParser` return an instance of `deleteCommand`.
-* Step 5. The `LogicManager` calls the `execute` method in `deleteCommand`.
-* Step 6. The `execute` method in `deleteCommand` executes and calls `deletePerson` in model to remove doctor or patient from the system.
-* Step 7. The `execute` method in `deleteCommand` also iterates through the `ObservableList` and retrieves all appointments that have the person to be deleted, and calls the `deleteAppointmentCommand` as well.
-* Step 8. Success message gets printed onto the results display to notify user.
-
-The sequence diagram below closely describes the interaction between the various components during the execution of the `DeleteCommand`.
-
-
+* Step 1. The `execute` method of the `DeleteCommand` is called.
+* Step 2. The `getFilteredPersonList` method of `Model` is called and finds its length.
+* Step 3. The `getZeroBased` method of `Index` is called to convert the provided index to its zero-based equivilent.
+* Step 4. The provided index is checked against the length of the current list of people.
+ * If the provided index is out of bounds, a `CommandException` is thrown.
+* Step 4. The `deletePerson` method of `Model` is called to remove the designated person from the list of people.
+* Step 5. An instance of `CommandResult` is created with a success message for the execution of `DeleteCommand`.
+* Step 6. The instance of `CommandResult` is returned.
+
+The sequence diagram below closely describes the interaction between the various components during the `execute` method of `DeleteCommand`.
+
+
Why is this implemented this way?
diff --git a/docs/diagrams/AddPatientCommandExecuteSequenceDiagram.puml b/docs/diagrams/AddPatientCommandExecuteSequenceDiagram.puml
index 99c67c17f57..0a6cef51d0b 100644
--- a/docs/diagrams/AddPatientCommandExecuteSequenceDiagram.puml
+++ b/docs/diagrams/AddPatientCommandExecuteSequenceDiagram.puml
@@ -19,18 +19,18 @@ end box
activate AddPatientCommand
-AddPatientCommand -> Logger: log(Level.INFO, "Duplicate")
-activate Logger
-Logger -> Logger: log
-Logger -> AddPatientCommand
-deactivate Logger
-
-
alt model.hasPerson(toAdd)
AddPatientCommand -> Model: hasPerson(toAdd)
activate Model
Model -> AddPatientCommand
deactivate Model
+
+ AddPatientCommand -> Logger: log(Level.INFO, "Duplicate")
+ activate Logger
+ Logger -> Logger: log
+ Logger -> AddPatientCommand
+ deactivate Logger
+
[<--AddPatientCommand: throw CommandException()
else else
AddPatientCommand -> Model : hasPerson(toAdd)
diff --git a/docs/images/AddPatientCommandExecuteSequenceDiagram.png b/docs/images/AddPatientCommandExecuteSequenceDiagram.png
index f0d94cc7a00..073bc4758d9 100644
Binary files a/docs/images/AddPatientCommandExecuteSequenceDiagram.png and b/docs/images/AddPatientCommandExecuteSequenceDiagram.png differ