Null vAlues and If statement

Hello I have a data export that is not the cleanest.  When Importing under the "name" column all the null values that are under Jessica Bayne, relate to her.  All the null values under Casey, those relate to her.  Is there a way I could do some sort of if statement such as if value is null , copy the value in the cell above?  I'm not sure if a new column would need to be made to accomplish this.  Any help is appreciated.  Thanks.