Yes it can, with certain conditions.
Your existing insurer will assess the risk of your new van and if it is happy to insure the new vehicle, they will simply amend the policy to cover to the new van and charge you any additional premium for insuring it up until your renewal date.
If the risk is a lesser one, then you may be due a return of premium, although this will depend on whether you have had any previous claims that year on your policy.
Also, some insurers now charge an administration fee for making changes on your policy.
Sometimes though, your current insurer may find the new van to be an unacceptable risk for one reason or another.
As an example, some insurers will not insure vans with more than three seats.
If this is the case, a ‘return premium’ for the unused portion may be issued to you for the remainder of your policy term.
As mentioned above, this will not apply if you have already made a claim on the policy.
In this case, your van will need to be insured by another insurer who is prepared to take on the different risk.
There are two further things to note in this instance.
1. A return premium is not always calculated on a pro rata basis and is sometimes based on a percentage of the original premium. The insurer’s policy booklet will detail exactly how it is calculated.
2. Your new policy will commence on the date the new van is to be insured, and therefore you will have a different renewal date.