Local pharmacy filled Rx for valsartan HCT from Mylan mfr. My mail order filled 90day Rx with pills from Sandoz mfr. Is it ok to switch between mfr’s?

These are generic meds and are manufactured by multiple companies so different insurers will purchase then drugs from different venders. Given that they are Diovan or valsartan they are the same active ingredient even though they look different. Just make sure that they are the same medicine.