Edit contents of Modal popup in R shiny

I would like to edit the contents of a modal popup in R shiny. Below is my code with which I'm able to print the values in the modal popup but I'm not able to edit it.


modelnetlist <- function(failed = FALSE){
    netlistdata <- readLines('run.scs')
    splitText1 <- stringi::stri_split(str = netlistdata, regex = '\\n')
    # wrap a paragraph tag around each element in the list
    replacedText1 <- lapply(splitText1, p)
      title = "Netlist File",
      easyClose = FALSE,
      footer = tagList(
        actionButton("save", "Save")

  observeEvent(input$gennet, {

**run.scs file:** (File that I'm calling in modelnetlist function to read and display it in the modal)

Simmulator lang=spectre
global 0
paropt options redefinedparams= ignore 
parameters vnw=0 vnd=0 
parameters area_1=5.5e-12 

I would like to edit in the modal popup, but I'm only to print with my code. I tried textInput, textOutput inside modalDialog but it doesn't help. Any suggestions?