Apple Music Subscription

I currently have an Individual Apple Music subscription paid for via my mobile phone provider EE as part of my monthly contract with them.

my partner has an individual Apple Music Subscription as well and the free trial period has just expired.

i think it would be best to upgrade mine to a family membership but am unsure if I can as its through my mobile phone provider. I would rather do it through mine as I have had mine the longest.

can I just upgrade or do I need to transfer it from EE first.?