After passing the end date of the contract, the contract is expired and cases cannot be opened against it. To open a new case against the contract, renew the contract.
When you renew a contract, a draft copy of the contract is created with the same ID number as the original, expired contract. You can make modifications to the new draft contract, including adding or modifying contract lines. You have the option of including contract lines that were canceled from the original contract. After the original contract expires, invoice and activate the renewed contract.
A renewed contract has the same ID number as the original contract, reflecting the renewal action in the contract's history. The start date is automatically set to the day after the existing contract expires. While Microsoft Dynamics CRM gives the renewed contract the same duration as the original contract automatically, you can change the duration manually.