Repairing lawn dips isn’t difficult - as long as you take your time to work carefully. First, cut around the dipped area with a spade - make sure to cut where the lawn is still level. You can mark squares or rectangles, but always leave one side of the dip uncut. Next, lift out the lawn from underneath - ideally, you should dig out a layer around one inch thick. Start lifting the lawn opposite the uncut site and gradually move towards it. This should be done slowly and carefully to prevent damaging the lawn and soil. Roll the lifted lawn towards the uncut edge and leave in place. Rolling the lawn will uncover the hole in the soil. Fill and level the dip with topsoil - feel free to use any excess soil already in your garden. Press down the soil as tightly as you can. Finally, roll the cut lawn back into place. Make sure the edges are in line and pressed down carefully. Thoroughly water the area until the roots regrow, taking extra care with the edges. If the edges dry out, they can shrink and create gaps in the lawn. Some lawns might benefit from adding fertiliser, too.