Can't update schema while OpenEdge Replication is active

Can't update schema while OpenEdge Replication is active.
User updating schema is waiting for a schema lock.
Schema is not being applied.
Other users are accessing the target database.

The default OpenEdge Replication parameter setting for schema-Lock-Action=wait. 

This means that a user who is trying to update the schema online will wait until all users exit the database. 
Once all users exit the database, then the user updating the schema can obtain a schema lock.

In order to apply schema updates online without waiting, it is possible to change the default behavior with the schema-Lock-Action property first introduced in OpenEdge 10.1A. It is set in the [server] section of the repl.properties file:
schema-Lock-Action=force

When the force option is set, the replication agent will attempt to acquire the exclusive schema lock five times.  If the fifth attempt fails, the agent disconnects all users from the target and makes another attempt.  If the last attempt fails, the server and all agents terminate. This allows the source database to resume normal activity.  When schema update activity completes, the server and target can be restarted.

In order to change replication server properties online, the replication server needs to be stopped. Refer to Article: P135112, Do replication source and target databases need to be shutdown to change the schema-Lock-Action parameter from wait to force?   

References to Other Documentation: 

OpenEdge Replication: Users Guide, Chapter 1: "Special Database Considerations".

Progress Article: 
P135112, Do replication source and target databases need to be shutdown to change the schema-Lock-Action parameter from wait to force?   
P107248, Cannot apply .df file while Replication server is running - error 2623