Each House considers the other’s amendments
When a bill has passed through third reading in both Houses it is returned to the first House (where it started) for any amendments made by the second House to be considered.
What is ping pong?
If the Commons makes amendments to the bill, the Lords must consider them and either agree or disagree to the amendments or make alternative proposals.
If the Lords disagrees with any Commons amendments, or makes alternative proposals, then the bill is sent back to the Commons.
A bill may go back and forth between each House until both Houses reach agreement on the exact wording of the bill – this is known as ‘ping pong’
What happens after consideration of amendments?
When the exact wording has been agreed by the Commons and the Lords, the bill is ready for royal assent. Once a bill receives royal assent it is made an Act of Parliament (the proposals in the bill become law).
In exceptional cases, when the two Houses do not reach agreement, the bill falls. If certain conditions are met, the Commons can use the Parliament Acts to pass the bill, without the consent of the Lords, in the following session.