Yes.
You must authorise the money transfer within your bank app(s) in order for a transfer to take effect. You can change your mind any time up to the point of this authorisation.
If you have authorised the money transfer, and then change your mind, don't worry. If you are transferring your money using the Marygold app you are only ever transferring funds between Marygold and/or non-Marygold accounts you control. If you need to move the money back, then simply do another me2me transfer in the opposite direction.