How to renew the encryption certificate in SQL Server 2016?

Question

I have implemented SQL Symmetric key encryption by using the below scripts in SQL Server 2016. 

CREATE MASTER KEY ENCRYPTION BY
PASSWORD = 'xxxxxxxxx'
GO  

CREATE CERTIFICATE EmpEncryptionCertificate
WITH SUBJECT = 'Column-level encryption certificate',
EXPIRY_DATE = '20191231'; 
GO

CREATE SYMMETRIC KEY EmpSymmetricKey
WITH ALGORITHM = AES_256
ENCRYPTION BY CERTIFICATE EmpEncryptionCertificate
GO

 

Article used for reference:

 

https://www.c-sharpcorner.com/article/implement-column-level-encryption-decryption-in-sql-server-2016/

I have kept the expiry date for the certificate as 20191231. Can we renew this certificate with a new expiry date? If yes, how to renew this certificate during the expiry period?

If not, what needs to be done ?

 

Will the encryption work even if the certificate is not renewed?

 

Thanks in advance.