ASP.Net 4.5 to ASP.Net core 2.0.1 migration

Hello All, PLease help to migrate EF 6.2.0 to EF core 2.x version, My current web application is using EF 6 code first approach to create DB, now i would like to migrate the EF framewoek to core with new columns added, my configuration is using DropCreateDatabaseIfModelChanges, i don't want to lose data in the DB for recreation.  What are the options to achieve this migration?

Thanks in Advance,

Geetha