Restore the DB, Showing DB in use In AX 2012

Recently I was facing some issue while restoring AX database, whenever I try to restore the Transactional DB its show error "DB is use" while actually this DB is not used anywhere. Than I try to take take the database offline, But again there was one other issue.

Same issue again DB offline taking very long time.
I tried below steps and this worked for me. :) 
Step 1: Try to run below two queries in same given sequence. 

i. ALTER DATABASE <DBNAME> SET OFFLINE WITH ROLLBACK IMMEDIATE

ii. ALTER DATABASE <DBNAME> SET Offline

Step 2: Now try to take offline manually. 


Step 3: Restore the DB.
Step 4: Some time after doing restoration/backup DB will not work.
Than u need to roll back above query operation 
ALTER DATABASE <DBNAME> SET online WITH ROLLBACK IMMEDIATE 
ALTER DATABASE <DBNAME> SET online.