You can call it by including it in the code of the button. You can also use the Call statement.
Call Text1_AfterUpdate
I wonder why you want to do this. There is great potential for problems. Imagine that the user types something in the textbox and then clicks the button. The After_Update event would fire twice, consecutively. Depending on what happens in the After_Update event, you could get undesired results. Terry Broadbent
"The greatest obstacle to discovery is not ignorance -- it is the illusion of knowledge." - Daniel J Boorstin