Patching files

hey im trying to patch files like .exe's and .dll's, so far i have:

Open "File.exe" for Binary as #1
Put #1, "&H00006291","01023"
Close #1

that was just a example, but how would i replace the offset "00006291" with "90909090" ?
i cant figure it out, can someone help?

I'm not sure I get the question.

If Put #1, "&H00006291","01023" works, then why would you not expect If Put #1, "&H90909090","01023" to work ?