What should I do if my garment is soiled with urine impurity while I am at work and do not know how to purify it, and the time for Dhuhr prayer has arrived, bearing in mind that I finish work after Asr prayer and then go home?

If your garment is afflicted with the impurity of urine or other impurities, it must be purified for prayer by immersing the area of impurity in water. It is not obligatory to change the garment. If you are unable to purify it due to the absence of water, or a place to wash, or if it necessitates uncovering your awrah, then you pray according to your circumstance; for Allah does not burden a soul beyond its capacity, and avoiding impurity is waived when one is unable to do so.