amazon rds – How to reduce size of my RDS mySql database of 5000 GB to 2000 GB, with all the triggers and functions intact?

I have a RDS MySql database of provisioned storage 5000 GiB. Out of 5000 GiB I am using only 1400 GiB and want to reduce size of provisioned storgae to 2000 GiB. All the tables are innoDb.

I want to keep my triggers, indexes, keys and functions intact.

What will be the simplest and most fail proof approach to achieve this ?