Update estimate within a Prime Contract without having to delete the Prime Contract

You create a Prime Contract, bring an estimate into it. Then the estimate changes and you CAN NOT bring it back into the same Prime Contract (does not refreshes the previous). The only solution is to delete the Prime Contract and do it all again. But the worst thing is only yet to come: YOU CAN NOT delete the Prime contract if there are; schedules, specifications etc. So imagine: You have to delete ALL and DO THAT AGAIN !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!