Short strangles are very high probability trades with option far OTM it is important to make adjustments slowly with these types of strategies. That said, if the stock moves towards one end of the strategy quickly you'll want to first adjust the size of the strategy that the stock is moving away from by moving that option closer to the money.
Let's assume a stock is trading at $50 and you have the $45 put and $55 call strangle. If the stock rallies up closer to $55 call side you would move UP the put side from $45 to $48 or something along those lines.
And unlike what you've probably been told before in the past you should never move the side of the strategy that the market is moving towards. In our example above you would never move the $55 call higher.
Rolling one side out and up only opens up the door for compounding losses should the stock continue to move in that direction.