How can I fix pool liner from pulling away from return hole?

To fix a pool liner that is pulling away from the return hole, first, drain the pool to a level below the return fitting. Carefully reattach the liner by smoothing it out and ensuring it is properly seated around the return hole. You can use a pool liner adhesive or tape for added security, and then refill the pool, ensuring the liner is evenly distributed as the water rises. Finally, check for any leaks around the return fitting and adjust as necessary.