What would you do if you received a negative feedback about one of the training workshops you've arranged for the company?

Understand in detail the reason for negative feedback from the group, analyse the same.

See if the objectives for the training workshop that you had though were met or not. Basis that retrospection take an action.

There are times when people give a negative feedback on training because they think it has NOT added any value to them. Diagnose that & take it forward.

Always remember negative feedback make you learn more...