Mutiple Appointments for same applicant

[PR2005]

Hi,
I am sponsoring visitor visa for my parents and have taken the web appointment on July 18th at Calcutta Embassy.Can I also take another appointment simultenously just in case if the visa is rejected, my parents can reapply immediately.Or I can take next appointment only after the visa is rejected.

Is it possiblle to take more than one appointments at a time for same applicants?

Is there any other way to reapply sooner than taking another appointment if visa is rejected?

Please provide me correct information on this.

[immihelp]

You can only take one appointment at one time.

There is no other way to get faster appointment in case rejected.