Multiple sales persons in POS


I am new to AX retail , I have a small query regarding AX retail POS. In POS we have an option where we can enter the sales person code while doing the transaction.

Now if there is only 1 sales person for the transaction it’s working properly, but if I have more than one sales person in transaction system replace the previous sale person with the new sales person.

I just want to know is there any specific setup for this which am missing in case of multiple sale person.

Thanks a lot in advance.