For people who need to travel quickly, the Super Priority and Priority Visa services are available. The process takes 3–5 days for Priority Visa applicants, but only a single working day for Super Priority Visa applicants
To begin, contact the Home Office and ask for a priority slot. If the priority slot is approved by the Home Office, you will be assigned a code, which will often begin with two letters and five numbers. When it comes time to pay the visa cost, you’ll need this.
If you’ve already applied for a visa in standard mode but want to change the type, you can do it here. You will not be able to amend your application to priority service once it has been submitted. The only option is to withdraw your application and resubmit it as a priority service application.