(1) Explain your problem, don't simply post "This isn't working". What were you doing when you faced the problem? What have you tried to resolve - did you look for a solution using "Search" ? Has it happened just once or several times?
(2) It's also good to get feedback when a solution is found, return to the original post to explain how it was resolved so that more people can also use the results.
you have 2 options
option #1
copy the project then delete the codes then export it and give it to the client
option #2
during the import process on the Update Project Options have the client select modify
in the data type: global under the Assignment Code click in the action column and change the action to do not import
also under the Assignment Code Values click in the action column and change the action to do not import
in the data type: Project under the Activity Code Values click in the action column and change the action to do not import
also under the Activity Codes click in the action column and change the action to do not import