You will need to call so they can put the upgrade through for you.
150 is the free number to use from a Sky Mobile or Sky Talk phone otherwise under "Need more help ?" link at the bottom of the page on this link is the number to call Sky on:
https://www.sky.com/help/home
When you do call say nothing when the bot speaks to you about what your call is about as it should then route you to somebody.
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