How to change primary key field dataelemet in customized table (ztable) ?

Dear Guru's,

I have created table.nd also created table maintaince generator.

i need to change primary key field domain element in that table..

i tried with se14 and se11.. but its not updated domain element. for that i need to give validation in

tgm.

Suppose company code  110 ..

tgm validate 110 company code only if give any other company code

through error message in tgm.

Regards,

syam.