promote a deferred standby without applying WALs

I have a standby database running 3 hours behind the primary (recovery_min_apply_delay = '3h').

In case of a logical error on the primary I want to promote the standby database which still has correct data.

The standby should not apply any more WAL in that case.

It seems that this can only be done manually:

1. pg_ctl stop
2. rm -rf standby.signal
3. set primary_conninfo = ''
4. pg_ctl start

Is there no single command on this?