A tenented premises which was under redevenlopment had a time bound clause of 24 months suo motto wh

A tenented premises which was under redevenlopment had a time bound clause of 24 months suo motto which it stands cancelled, but tenancy rights prevails untill permanent accomodation is handed over to tenanent on ownership bases. if the devenloper fails to construct & hand over permanent accomodation on ownership bases within time frame than tenent can enter & occupy the said property. clause further states that till the time devenloper make good losses of tenant caused due to delay or any other nature, the tenant will have lien on the property & he can occupy it. now my question is the time frame is about to end, rcc structure has just started upto 2nd floor, it looks as if it will take another 2 yrs. financial condition of devenloper is not good. what step should be taken by tenent. devenloper is asking for amendment in time frame? can it be done and registered. he does not have money to pay for rentAls for (18 MONTHS) extended period he want to give 6 X 3 months pdc's which is to be deposited as & when his funds will be available. please guide me, what steps to be taken.