use master
GO
select
d.name,
d.dbid,
spid,
login_time,
nt_domain,
nt_username,
loginame
from sysprocesses p
inner join sysdatabases d
on p.dbid = d.dbid
where d.name = ‘database_name’
GO
kill 56 => kill the number in spid field
GO
exec sp_dboption ‘database_name’, ‘single user’, ‘FALSE’
GO