I have seen the issue since 2011:

Signal and/or RPC call to re-read config file

Reload bitcoin.conf without restarting the program

New option and configuration framework:

New rpc command “reloadconfig” to dynamically update configuration parameters (Issue #309). Command line parameters will not be overridden. Notice that many core parameters are used only during startup.

But such command does not seem to exists.

Why do I need it? – it seems that adding an entry wallet=mynewwallet.dat will create a new mynewwallet.dat if it does not exists when the program starts. this is good since I want to be able to dynamically add wallets in a multi-wallet mode. but the program needs to restart entirely.

Is there an option I missed in Bitcoin Core RPC to reload the conf file? My version is 0.15.1

Thanks.