u can regrout or just take what is cracked and use caulking
Here’s a Hometalk link for you to consider. Hope this helps
Where is it cracked? If it is the bottom seam between the wall and the floor or wall and tub, it should be caulked not grouted. Same is true for inside corners where walls meet. If necessary, remove the grout and caulk.
Remove and re-grout. Then seal.