Betty R wrote:
I need assistance to switch one tracker history to another
That is not possible. (You mean you tracked time to the wrong contract?)
Take screenshots of the segments in the wrong contract, then delete them so the wrong client does not get charged (if it is for this week)
Then ask the right client if you can add manual time to their contract, explaining what happened and showing him/her the screenshots you took of the time you logged to the wrong contract.
If it's from a previous week, you can't delete the time, only refund the client.