Simple If Statement Syntax

I am trying to create a field for our task table header that will combine two fields

For example - Client Name and Transaction Name.

The issue is that some records have a client name and transaction name and some will have one and  not the other.  So I need the formula to look if the field and display either both or the one that has data. 

If ( >" ", ),
//if ([Contact - Full Name] >" ", [Contact - Full Name])

The fist line of code works, I cant seems to get the right syntax to combine them into the new field

Thanks.

------------------------------
EF
------------------------------