Nested If problem with hours columns

[Anonymous]

Hello everyone, i'm having a little trouble with this If statement, where i'm trying to check by the "EndHour" if its "Morning" or "Evening" shift. Everything works perfectly from this point:

= Table.AddColumn(#"Renamed Columns1", "Shift", each if [Hora_Salida] <= Time.FromText ("4:30:00 PM") then "Matutino" else "Vespertino" )

But i found that theres some records where the "EndHour" is "Null"  but i do not know how to use the nested if to check that if the "EndHour" is Null then to compare with the "StartHour" 

Will appreciate if anyone can help me with it

[amitchandak]

@Anonymous , Based on what I got, change as per need

Table.AddColumn(#"Renamed Columns1", "Shift", each if [Hora_Salida] <> null and [Hora_Salida] <= Time.FromText ("4:30:00 PM") then "Matutino" else "Vespertino" )