Okay so my 5 month old daughter is so close to rolling over from her tummy to her back the only…

Okay so my 5 month old daughter is so close to rolling over from her tummy to her back the only problem is she'll just lay on her side and stop then roll back on her stomach. is there any way I can help her to roll over on her back? cause all she will do is roll on her side and then give up.