How to automatically extend contracts?

Hello,

when a customer does not cancel his contract until the cancellation date the next possibel cancellation date and the new contract end would expand according to the cancellation conditions.

Example:

The contract runs from 1.1.2015 until 31.12.2015. If the customer does not cancel his contract until 3.12.2015 the contract would be prolonged another year with the possibility of cancellation until 4 week before contract end.

So, if on 4.12.2015 the customer has not cancelled his contract therefore the new contract end shoud be 31.12.2016 and the new cancellation date 3.12.2016.

I've been searching if SAP offers a report to change these data automatically in the contract but couldn't find anything so far.

How do you handle automatic extrensions of contracts?

Thank you for your ideas.

Julia.