TweetUse the same exercise for both-. It's best to not really think of things in phases like that too. You can do both at the same time.
If you need to lose weight/fat- keep up the intensitity in the gym and focus on eating cleaner. If you need to gain muscle, find how many cals allow you to grow and make sure you hit those. Also pay attention to your macros (% carbs, %protein, and %fat) and work with those numbers to keep gains as lean as possible.
If you need to lose weight you want to be in caloric deficit, to gain you need calorie surplus. But adding muscle causes you to burn more cals and will help burn fat, so in that sense you can do both if you eat clean. Going into calorie defecit can eat up some muscle along with the fat too.
Its all about finding how your body reacts to what you eat and how you train. But for losing weight or gainging weight- the gym should stay the same, as big and intense as possible. Make sure you are eating enough food and make sure the food is clean as possible.