list feed update row question

[Khan]

when I update a row using the listfeed, is there a way to just update "SOME" 
of the columns in that row?
 
it seems like the call will clear out the data in columns that I am not 
updating for that row...
 
this seems somewhat illogical...
 
I have many columns and I don't want to repopulate all those columns with 
the same data when I update.
 
thanks