As per my knowledge, I do not think there is a direct way to identify only the renamed column tables and then just reload them.
Do you rename the field from the LOAD statements itself or you use the in-built RENAME statement in qlikview?
Workaround can be, to binary load your data model into another qlikview file and in the new one add the RENAME statements. Though this will still reload all tables, but will be relatively faster.
P.S the workaround is not tested by me.
Hope this will be helpful.
Partial reload is the option or you can comment the old field and reload only those fields only. And another way is load another table with partial load and join this table to the old one or concatenate the table. But better you rename the old field with new and do partial reload.
Load * From Location;