Sandeep, Why would you have to change the DBID of a database? My understanding would be to make the change at the sysdatabases table, and then you may have to restart the SQL Server in order to push the changes through the sysprocesses table. But there may be other tables involved such as sys.changes or the sys.master_files. It also goes by database_id in these tables. In other words, it would be a considerable undertaking, and I know of no tool to help here.
Altering any system tables is a bad idea for any purpose. I wouldn't recommend it without the explicit blessing of Microsoft Support. Doing so without them, IMHO, is bad mojo. One option would be move the database to another instance that have less databases thus allowing it to come online as quickly as possible. Maybe by itself if it is that critical in nature. Another option would be to tightly manage your transaction logs to ensure that any recovery is as minimal as possible as the database comes online.
do not start modifying the system tables, you're asking for trouble. The database id is populated throughout the system. One way to shift the IDs would be as follows (try in a test system first); 1. find database that occupies ID 5 and take backup then drop it. 2. backup your database to shift then drop it 3. restore the database you want to shift to ID 5 4. restore the database that ID 5 originally which will now get a higher system ID