How can a liner on 1998 Jaguar be replaced or corrected in place?

The liner on my 1998 Jaguar is sagging, How can I correct this so as to open my windows while driving.|||Take it to an upholstery shop, have them install a new headliner. It's not worth all the trouble of tacking it into place when it's only $100-300 to fix it right.|||they make glue for that yes any parts store would be beter if you removed it but can do it in car|||Any upolstery shop would be glad to fix it for you