Change key of existing score

There are times when I need to change keys of existing scores due to limitations of vocalists. This was/is easy in Sibelius. Two clicks and accidentals are adjusted globally. At the moment, Dorico requires me to manually change individual accidentals after I change keys.

What am I missing?

Select All, Write > Transpose, ensure that the tickbox to transpose key signatures is ticked, click OK.

Thanks. I was looking on a different area instead of the top menu. Solved.

How to do this in iPad? Write where?

Welcome to the forum, Tom! You can transpose in the iPad version via the entry in the contextual menu accessed via the secondary toolbar. More details here.