You must give IELTS again and revise your score before IELTS get expired. Thats the basic thing an apllicant is to make sure in Express Entry. The IELTS score, The passport expiry, The WES expiry, POF and many such things are applicants basic things which shall be monitored.
If for some reason you are not able to then you can create a new Profile and request PNP program to transfer your PT to the new profile. Find out the best way to give exam and make new profile. In this case you are relying on PNP not to check your score between expiry of IELTS to new IELTS. If they check before the new IELTS are in and find your IELTS expired they will reject the application.