Now a days, many mobile has hybrid sim slot, we can't use 2 sim and a micro sd simultaneously. To solve the problem, i did the following for my Redmi Note 4.
Step 1: Hybrid Slot Has Only 2 Slot, Either 2 Sim or 1 Sim and 1 Micro Sd
Materials--- instant gum, forceps, candle. one micro sd and 2 sim cards.
First gently hold the sim in corner with forceps and hold it above the candle flame with slow to and fro movements. within 4-5 movements the plastic case becomes soft and the main metal module comes out easily, carefully handle it.
Now put a drop of instant gum on the micro sd and place the module over it, gently press.
you are done.
carefully place the modified micro sd cum sim combination into the micro sd slot and push to the mobile socket.
Now you are able to use dual sim with a micro sd in the hybrid slot.
I did this for my Redmi note 4 and it is working perfectly.