Sorry – you didn't actually say what product you had, and my psychic abilities being limited, I mistakenly assumed you had an H9.
But, it appears you have a TF, so I am completely wrong. Let's start again.
TF is bank-based, where each bank is a group of two presets, so you can't easily decrement presets. Your best bet will be to use an external AUX switch (such as the BARN3, but many other switches are suitable).
Look at "[AUX SW] – Program Auxiliary Switches" on pages 47/8 to see the AUX switch options. Among them are BANK+ and BANK-, which allow you to increment or decrement the current bank.
This is probably as close as you will get to what you want.
