Sending vat return to hmrc, won't go says to click save again to make change that is prior to closing date where do i click safe?

Hi there, sheilster22.

I would like to share with you some insights on how this thing can be done safely.
 

In QuickBooks Online, changing the date range can only be done on the very first filing. Can you share with me if you've filed the first return already? If yes, the start date of subsequent filings will be set as the day after your previous filing.

I can see that you're unable to change the date as well as the system won't go through saving it. It's advisable to contact the HMRC support as they take charge to help you get these things possible.

Keep me posted it goes, and I'll be around to assist you more. Take care!