You can use a combination of functions...like
CDbl(Format(myInt, "#,##0"

)
The Format function returns the value you specify in the format you specify
Format(YourValue,YourFormat)
and works like...
Format(4.6798,"#,##0"

= "5"
the CDbl function returns a value specified in Type Double
CDbl(YourValue)
and works like
CDbl("5"

= 5
So - CDbl(Format(4.6798,"#,##0"

) = 5 and function looks like:
Function RoundMyVal(MyVal as Double) as Double
RoundMyVal = CDbl(Format(4.6798,"#,##0"

)
End Function
Hope this helps. I am sure there is probably shorter way of doing it, but that works for me.