# Review and billing status of time entries
Time entries in Aerion go through two independent processes: an **approval status** (whether an entry has been reviewed) and a **billing status** (whether an entry can still be edited and billed). Together they keep the approval and billing workflow clear and transparent.

:::lock{title="Required rights"}
Project-time / work-time approval (granted per team or globally)
:::

## Approval status

![](/images/guides/review-and-billing-status-of-time-entries/image-mqs7qa0p.png)

The approval status indicates whether an entry has been reviewed and approved. The possible statuses are:

* **Open** — the entry has been recorded but not yet submitted for review.
* **Submitted** — the entry has been submitted and is waiting for review.
* **Approved** — the entry has been approved and can be billed.
* **Rejected** — the entry was rejected. It can then be adjusted and submitted again.

When an entry is billed, its approval status automatically becomes **Approved** — even if it was never reviewed manually.

## Billing status

![](/images/guides/review-and-billing-status-of-time-entries/image-mqs7p3th.png)

Whether an entry can still be edited and billed is governed by two separate states: its **lock state** and its **billing state**.

### Lock state

* **Unlocked** — the default. The entry can be edited and billed.
* **Locked** — the entry has been locked manually and can no longer be edited or billed.

Locking is generally used to exclude entries from billing — for example, entries that were billed outside Aerion.

### Billing state

* **Uninvoiced** — the entry has not yet been billed and can still be edited and billed.
* **Invoiced** — the entry was set to *Invoiced* as part of issuing an invoice.

An entry that is **Unlocked** and **Uninvoiced** can be edited and billed; from there it can be either invoiced or locked.

## How approval and billing interact

The two processes are independent, but connected at one point: as soon as an entry is billed (billing state **Invoiced**), its approval status is automatically set to **Approved**.

This ensures that only approved entries are billed — either reviewed manually, or approved automatically as part of invoicing.

See also: [Check work and project time](/guides/check-work-and-project-time) and [Bill projects](/guides/bill-projects).