You can drop searchable columns from a replication definition only if they are not used in subscription or article where clause.
Use drop subscription to remove any subscriptions in which you want the where clause to exclude the searchable columns you are dropping. See “Using the drop subscription command”.
Use alter replication definition to drop the searchable column. For example:
alter replication definition publishers_rep drop searchable columns zip
(This example removes the zip searchable column from the publishers_rep replication definition.)
See “alter replication definition“ in Chapter 3, “Replication Server Commands” in the Replication Server Reference Manual for more information.
Use create subscription to re-create subscriptions to the altered replication definition. See “Using the create subscription command”.