We have a picklist field that we've been using to populate a field that's the basis for many reports that are created annually (for a school year). Going forward, there is a need to change some of these values -- mostly we're consolidating two values. 

We do  NOT want to affect the reports that have already been created for this year.

We only want the new picklist values to be the basis for reporting going forward. Of course, we understand that this will change the design of some of the reports going forward. 

What I would like to do is change the picklist values so that the old values remain the same. And the new values only apply to the next school year.

Is there any issue with that? Can new picklist values be added, and other values be removed WITHOUT affecting preexisting records?

Thanks,

Kim