Switching between KOReader and Inkpad 3 soft

Hello there and sorry to bother you with that,

I've replaced my defective (but fortunately still under warranty) Kobo Aura One by a Pocketbook Inkpad 3/740 received Monday and I managed to install KOReader without any hassle.

To benefit from such nice features as Text-to-speech and MP3 listening availlable with the original Pocketbook provided software, I would like to be able to switch between KOReader and the generic reader software: any idea or practical hint please ?

Thank you for your so appreciated help as ever and happy reading (and programming of course),
Germain