You can do it on exchanges that support future trading. All you have to do is to change it from one-way mode to hedge mode.

One-way mode
This means ones a position is opened, you can not add asset to it to increase your liquidation price range so the chances of getting liquidated is not reduced.

Hedge mode
Assuming you open a short position for bitcoin, but Bitcoin price increase, and your funds is about to liquidate at $$45000 as bitcoin price is increasing, if you want to be able to add more collateral to your future account, the you would have changed the one-way mode to hedge mode so if you transfer more asset to your future account, the risk of getting liquidated will reduce as the price can change from $45000 to a higher price.