Question: how do you change your percentage in tsp?
Answer: Go to myPay and log in.
Under the “PAY CHANGES” heading, select the “Thrift Savings Plan (TSP)” link.
Select the yellow pencil icon to make a change to your TSP contribution.
In the resulting pop up window, enter the changes you want to make. ... 
Select the “Continue” button to move to the “Review” stage.