One more alterneative will be..
Select Phone, F_Name, L_Name into #tbl1 from yourtbl where 1= 2
Select distinct phone,’ ‘,’ ‘ into #tbl1
Update #tbl1
Set F_Name = b. F_Name, L_Name =b. L_Name
From #tbl1 a, yourtbl b
Where a. phone = b. phone
If this is the way the data is going to be used I would redesign the table..