how to change a repeating rhythm?

I have a lot of bars with notes in a repeating rhythm. I want to change the rhythm of the notes to another repeating rhythm but keep their pitch.
Do I have to do it manually or can I change the rhythm in all the bars in in one go - without affecting the pitch ?

It’s very quick to alter the pitch of a repeated rhythmic pattern (repeat the pattern, then set the caret at the start, hit L and type/play the pitches). Unfortunately there’s no equivalent for retrospectively adjusting rhythms in bulk. The only exception is converting straight repeated notes to dotted ones (select passage and hit “.”).

ok - thank’s!
Manually it is then…

If there’s no music written after you can always use insert-mode.
Press I and then manually manually change each note. (Move with the left/right arrow and select the appropriate duration)
If you don’t want to mess up music after the passage you can always copy the section to an empty space and make the changes.

Sure, but that doesn’t solve the issue of how to change a repeating rhythm, which is what the question was about.