Requirement:- we need to convert a multi-select picklist value into single select picklist value.if We change the Multiselect to Single .how we can avoid data loss
We will be losing data if Changing from multi Picklist to any other type. It's not possible to avoid while conversion but we can do with apex data loader with minimal risk.
- Take a backup
- convert to picklist
- Remove multi select to single value in csv file with respect to your requirement
- upload into salesforce.