Abap Query select-options memory id

Hi

I am facing a problem regarding variant in a query. The field below is always repeating the last value in the selection-screen.

select-options SP$00001 for VBRK-VBELN memory id VF

For example: The variant V1 has the value 234567 in the field SP$00001. After run the query with this variant, I will run the query again withn variant V2. In V2 the field SP$00001 is empty, but the old value (234567) is been repeated.

I know that it is because of the memory id command, but how can I remove this command from the abap query?

Thanks in advance.

Joao Gaia