Repotting should provide relief for plants stuck in too-small containers with crowded roots or plants that just aren't thriving with existing conditions. It should not lead to wilting. When a plant wilts after repotting, it could be transplant shock or a change in plant care or plant environment. You've got to determine what's wrong before you can help your plant recover.
After repotting, plants often enter a state of transplant shock as they adapt to the new environment and get over the shock of being uprooted and moved. Symptoms of transplant shock include leaf drop or defoliation. If you notice a lot of lost leaves and poor quality of existing leaves, your plant might need some time to recover post-repotting. It should perk up soon.
Causes of Wilting
If your plant has only wilted leaves and no lost leaves, chances are something else is going on that coincided with the repotting. Leaves wilt when plants receive too much or too little water, or when the plant is cold. If you also moved the plant after repotting, it may do better in the old environment. If the soil is bone dry, your plant needs water to perk the leaves. Plants that have waterlogged soil can also fade or wilt.
Excess heat stresses out plants. Some wilting may be due to high humidity or changing temperatures. A natural cause may be behind wilting if your plant has adequate water, has not experienced a change in location and doesn't appear to be suffering from transplant shock. In this case, try to make the plant more comfortable by moving it to a cooler location or offering addition water to counteract a heatwave.
Plants are sensitive after repotting. While there's not much you can do to change the weather, providing the right care for your plant right after transplanting can help it recover and can prevent wilting due to improper water. Give your houseplant adequate water and light based on normal procedure for that type of plant. With time, wilting should reverse and your plant should recover.