I want to mount plumbing pipe on dry wall as a curtain rod. I have dry wall anchor screws. The style of curtain I have will require me to remove the bracket from the wall to be able to take the curtain down (to wash it). Once I put the screws in with the anchors, can I remove the screws later without ruining the anchors?
Replace the plastic anchors with small wing bolts. If you have to remove the pipe again, don't worry about losing the wing part of the bolt since it will drop down inside the wall. Just use another wing bolt when you reattach the pipe. There is the added benefit of a superior attachment vs plastic anchors that usually get loose and fail.
I don't know where you are, so while products examples mentioned are sourced in North America, they are widely available under different names.
(edit to add...) The bad thing about these is that they can come out with the screw if the connection between the drywall isn't great. (In other words, if they're put in badly, they can spin out.) (Thanks to @batsplatsterson for reminding me of this.)
Use these toggle anchors for the best results.
They are the strongest drywall anchors you can find plus They have the added benefit of the Metal toggle part having machine threads to except the machine screw so once they’re in place you can undo the screw as many times as you want without affecting the quality of the holding power. .