If you have been pumping 6 ounces at each session, pump 4 ounces, then 3, then 2, etc. By gradually expressing less milk less and less often your supply will decrease without causing physical problems for you. The amount of time it takes for your milk to dry up depends on how full a supply you have built up.
https://www.breastfeedingbasics.com/articles/lactation-suppression
Some mothers find that drinking sage tea a few times a day for 2-3 days can also help to dry up milk their milk. Steep a 1-½ teaspoons of dried sage leaves in a pint of freshly boiled water for ten minutes. Drink up to three cups a day for no longer than one week. Dried sage can be found at most health food stores.
http://kathleenhuggins.com/drying-up-your-milk-supply/
1 Use an anti-inflammatory medication, such as ibuprophen, as needed.  Do not pump. Pumping will signal your body to make more milk. Your body works on supply and demand. If you empty your breast, your body will think that it needs to make milk. When your breast becomes full it signals your body to make less milk.
http://www.justmommies.com/articles/drying-up-milk.shtml
1 Using drugs to “dry up” the milk is also not recommended because they are not very effective, and may cause serious side effects.  Wear a supportive (but not tight) bra for support. Choose clothing that is less likely to show wet spots if you leak, and wear nursing pads to absorb leaking milk.
https://www.breastfeedingbasics.com/articles/lactation-suppression
If you are sure that you do not want to breastfeed or if you cannot breastfeed, here are our best tips for drying up. 1  Wear a snug fitting bra.  Place refrigerated cabbage leaves inside your bra for a couple of hours or till they wilt. Cabbage leaves have been used for years to help relieve engorgement.
http://www.justmommies.com/articles/drying-up-milk.shtml
1 Take 200 mg of vitamin B6 each day for 5 days to relieve engorgement.  Sage tea contains a natural form of estrogen and can decrease your supply and help dry up your milk. You can buy it at the health food store, or use the spice from your kitchen. Take 1 tsp of rubbed sage with 1 cup of hot water and let it steep for about 15 minutes. You will want to add some milk or honey to it as it is very bitter. One full cup every 6 hours usually will usually dry the milk up quickly. Sage works best if you use it along with cabbage leaf compresses.
https://www.breastfeedingbasics.com/articles/lactation-suppression
The engorgement will come to an end after several days. Some mothers with a full supply may want to dry up taking at a slower pace by expressing milk only when feeling too full. By removing just a bit of milk infrequently one breast at a time, the production will slow and ultimately end. Double pumping will stimulate the milk more than single pumping does.
http://kathleenhuggins.com/drying-up-your-milk-supply/
1 Do not use cabbage leaves if you are allergic to cabbage or sulfa.  Use ice packs or frozen vegetables for compresses. Use cold compresses for twenty minutes a few times a day. Do not put ice or frozen veggies directly on your skin. Use a towel between the ice and skin.
http://www.justmommies.com/articles/drying-up-milk.shtml
1 Break up the cabbage leaves so that there are no hard veins in them. Arrange them in your bra so they are comfortable and there are no hard spots pressing against your breast. Do not use cabbage leaves if you are allergic to cabbage or sulfa.  Use ice packs or frozen vegetables for compresses.
http://www.justmommies.com/articles/drying-up-milk.shtml
If you have not made up your mind about breastfeeding, you may want to pump your breast milk until you decide. If you are sure that you do not want to breastfeed or if you cannot breastfeed, here are our best tips for drying up. Wear a snug fitting bra.
http://www.justmommies.com/articles/drying-up-milk.shtml
done breastfeeding how to dry up milk
To dry up milk after breastfeeding wear a snug fitting bra. To dry up the milk, wear a snug fitting bra when breastfeeding is done.