This is a touch subject as it really depends on the circumstances. People get offend most of time when they receive an invite and then later are told they are no longer invited. In many cases, make sure to check your budget to see if you can afford to invite them, and revise list as much as possible before inviting anyone. In the case you have, it would be better to speak to them, explain your situation and try to salvage your relationship with them. All the best.