You can change your plan type through the admin panel and the procedure is very easy.
Basically, you go to Billing -> Manage Account, click Edit on the plan you wish to change then choose the plan you wish to upgrade/downgrade to.
The following quote from the panel may be of interest;
[b] # there will be no downtime for anything.
feature changes happen immediately.
your plan's billing start date changes to today.
any pre-payment left over is credited towards the new price.
there is a $49.95 one-time set up fee if you pick a monthly billing cycle. [/b]
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