Any upgrades you make to your subscription will be applied immediately and your account will be charged the prorated cost up to the same date as the original purchase.
Any downgrades you make to your subscriptions will be reflected on your next billing cycle. If your account has recently renewed automatically for services that exceeds your current needs, please contact support.
Increase/Decrease Business Access user licenses:
1. Login at my.splashtop.com / my.splashtop.eu, click on the "Upgrade" button:
or click on your name/email at the top right of the page and choose "Subscriptions". Then click on "change".
2. Click on the "+" or "-" to change and show the payment information.
The computer limit is also increased by 10 per new user
* The new licenses are prorated up to the same date as the original purchase.
3. Click Subscribe at the bottom of the page after confirming payment info.
Note: Please refer to this article for more details on upgrading Business Access Pro
Remote Support - increase/decrease computer package license:
1. The process is similar to upgrading the Business Access service. Login at my.splashtop.com / my.splashtop.eu, then click on the "Upgrade" button
or click on your name/email at the top/right of the page and choose "Subscriptions", then click on "change plan".
2. Select the plan that suits your needs and then click Subscribe after confirming payment details on the same page.
* The upgraded package is the difference of the packages and prorated up to the same date as the original purchase.
Convert Business Access to Remote Support (or Vice-Versa):
Please contact our Customer Success team at customer-success@splashtop.com or call +1 (408) 758-5899 and we will be glad to help convert you over so you can purchase the Remote Support package online afterwards. (or vice versa)
Please look here to learn about the differences between Business Access and Remote Support and see which product suits your needs.
SOS - upgrade from SOS Legacy or Basic to SOS + Unattended:
1. The process is similar to changing the Remote Support service. Login at my.splashtop.com / my.splashtop.eu, then click on your Account Menu and select "Subscriptions", then click "change plan".
2. Select the plan that suits your needs. 
If you don't see the option available for upgrading to a SOS+unattended computers plan, you may be on an SOS-legacy plan, or have a conflicting active or expired Business Access or Remote Support feature. If this is the case, contact our Customer Success team at customer-success@splashtop.com or call +1 (408) 758-5899 and we will be glad to help convert your account so that you can complete your upgrade.