Personalised IDs for participants

Hello,
.
I hope this is appropriate to ask here but I am a bit lost. Is there a way to change personalised IDs for participants who have already answered questions out several times? We are able to change the contact lists, but when exported, participants names and personal information is recorded via excell files/SPSS. We are looking for a way to anonymise their names. As you can imagine, changing their names after weeks of output and thus hundreds of results will take a painstakingly long time and we are hoping to remedy this hopefully with some kind of Qualtrics technique which we are unaware about.

Thank you