hi can i change tourist visa to non immigrant visa

Yes plenty of threads on here on how to do it.

What category of non immigrant visa would you be changing to and upon what basis?

Yes, as a prerequisite to getting a qualifying extension of stay.

1 hour ago, keith40 said:

can i change tourist visa to non immigrant visa

How practical this process is depends on what immigration office serves the area where you live.  It is possible at most with the correct paperwork.  No problem at Bangkok, for example - but Bangkok will only process these for people living in their service-area (now).  At other offices, they don't want to do them, and it can be much easier to go straight to a consulate in a neighboring country to get a single-entry Non-O, then apply for your annual extension at the local immigration office after this.

Edited September 10, 20178 yr by JackThompson

OP.

Are you over 50 with 800,000 baht in the bank or 65,000 a month income or combination of the two eg 400,000 in the bank and monthly income to make up the figure to 800,000 baht per year?

Or married ( registered ) with 400,000 in the bank or income of at least 40,000 baht a month?

Edited September 10, 20178 yr by overherebc

OP can apply for non-o from his home country if he shows prove of planning to reside in Thailand like the will to buy condo and monthly sufficient funds like I did regardless of age requirement but it is all up to the embassy or consulate staff management.

1 hour ago, nasanews said:

OP can apply for non-o from his home country if he shows prove of planning to reside in Thailand like the will to buy condo and monthly sufficient funds like I did regardless of age requirement but it is all up to the embassy or consulate staff management.

There was a time when Non-O visas could be obtained by under-50s who were not married to a Thai, but I am not aware of that being the case anywhere recently.  It would interesting to find out how you managed to do this, and if you did so recently.