Changing time of party after invite?

[DeathMetalMum]

Dd invited to a party, small group going had invitation via a message as only a couple from dd's class are going. Responded dd would love to go thank you etc. Few days later receive a message saying time has changed, now the time clashes with a activity dd does weekly, which this date also happens to be the last class before the summer break. I'm not certain weather dd would have chosen to go or not knowing this and now she's not sure. Just wondering what others would do birthday party or class.

Personally, probably skip the class, but either is fine. If there is not much of an overlap she could go to part of the party.

Unless the last class means a show for parents I would skip it.

Whichever DD prefers, simply enough. It's a teaching opportunity about calender clash too!