how do I change the GST ITC postings and add a different GL account number?

Hi @I-J ,

Welcome to the Intuit Community! Making sure you're recording your transactions the right way is a good exercise for preventing errors in your books. I'd be happy to steer you in the right direction so you can focus on doing the things you enjoy. 

To ensure accuracy in your books, I recommend contacting an accounting professional to get more info on recording the transactions. Doing this will help prevent any future discrepancies in your books. If you're not in contact with one, I encourage you to search for one on our website using this link here.

I'll also leave this question here so other accounting professional members can chime in. Let me know if you have other questions. I'm here to help.