Does this look right?

When a couple of bits are true, I want set another bit and add a string
to a string.

But when it's a false condition, I want to subtract the string from the string.
I didn't see anything that subtracts as easy as the symbol & will add, so I guess you just make the string empty?

Code:
dim messone as string = channel1on
dim messout as string = results>

 If lowbit0 = True And c1 = True Then
            doit1 = True
            messout = messout & " - " & messone
        Else
            doit1 = False
            messout = messout.Replace(messone," ")
        End If
Thanks.