Tablet on Android 7 has 16Gb Sd card and I want to replace with 128 Gb card and not lose anything.

[unclesocial]

Tablet on Android 7 has 16Gb Sd card configured to be like memory (added to built in memory). How can I replace it with a bigger card and keep all the stuff that is on it? (Don't wanna lose anything).

 

[Rukbat]

You can't, unless you learn a lot about computers, and develop a program to copy the small card to the large card as a small card, then convert it to a larger card - something that not even a system developer would apply for a job for (I know - I spend over 30 years as a system developer). (Which is one reason to not format an SD card as internal - it's almost impossible to do anything with it and, when the card goes bad - and it will - you'll have to start from scratch, factory resetting the tablet.)

Your best bet is to back up the entire tablet (maybe using TWRP, if you can install TWRP without wiping the tablet - whether you can depends on the tablet make and model), switch cards (turn the tablet off, remove the small card, insert the large card, turn the tablet on, it will ask about formatting the card - format it as internal) - then use TWRP to restore everything.

That way it's only difficult and time-consuming. Doing it the way you want is like scratching your left elbow with your left hand.- aside from leaving you a bit crazy, it's painful.