ask the people who already approved the DA but it shouldn't be a problem although i'd ask how long before the approval for the pool expires rather than changing the DA just in case you want to add a pool in future and/or to include any time you wanted to sell the house with the pool approval included

Thanks for this advice. We have waited a while and DA approval for build will expire next year if the first shovel does not hit the ground by then. Thought we could save money omitting pool but I think we will probably go with original plan to include pool anyway. Thank you