curl --location --request POST 'https://api.inboxkit.com/v1/api/billing/subscription/change' \
--header 'Content-Type: application/json' \
--data-raw '{
"uid": "plan_123456"
}'
{
"error": false,
"message": "Subscription updated successfully.",
"plan": "Professional",
"uid": "plan_123456",
"features": [
"string"
],
"cycle": "monthly",
"renews_on": 1640995200,
"purchased_on": 1640908800
}