diff --git a/src/main/java/seedu/address/logic/commands/EditDeadlineCommand.java b/src/main/java/seedu/address/logic/commands/EditDeadlineCommand.java
index 1e6ef5f010d..d698f360c2a 100644
--- a/src/main/java/seedu/address/logic/commands/EditDeadlineCommand.java
+++ b/src/main/java/seedu/address/logic/commands/EditDeadlineCommand.java
@@ -63,7 +63,13 @@ public CommandResult execute(Model model, CommandHistory history) throws Command
 
         Task task = taskOwner.getTask();
         Task editedTask = task.editDeadline(deadline);
-        model.setTask(task, editedTask);
+
+        Person editedPerson = new Person(taskOwner.getName(), taskOwner.getPhone(),
+                taskOwner.getEmail(), taskOwner.getAddress(),
+                taskOwner.getDepartment(), taskOwner.getTags(),
+                taskOwner.getEfficiency(), taskOwner.getComment());
+        editedPerson.setTask(editedTask);
+        model.setPerson(taskOwner, editedPerson);
         model.commitAddressBook();
         return new CommandResult(String.format(MESSAGE_MARK_TASK_SUCCESS,
                 Messages.printName(taskOwner), deadline.toString()));