Hello
I assigned "Front-end item editing" access to an user in "k2 user groups" .
When this user assigned to "Registered" in joomla user groups , it opens edit page without modal . but when user assigned to "Editor" , edit page opened by modal .
How can open modal in front end editing for "Registered" users group ?

Hello,

Can you send me a screenshot of the markup for these two cases?
Also check your browser developer tool's console tab for any issues.

I Installed "jQuery Easy" plugin then problem Solved.

Nice to hear that you solved the issue :)