diff --git a/bot.go b/bot.go
index 6dacf16..bed3d62 100644
--- a/bot.go
+++ b/bot.go
@@ -52,6 +52,7 @@ func (b *Bot) BotHandlers() {
 	b.bot.Handle("/pause", botPause)
 	b.bot.Handle("/unpause", botUnpause)
 	b.bot.Handle("/register", botRegister)
+	b.bot.Handle("/deregister", botDeregister)
 	b.bot.Handle("/delete", botDelete)
 	b.bot.Handle("/companies", botCompanies)
 	b.bot.Handle("/clients", botClients)
@@ -170,6 +171,35 @@ func botPlayers(m *tb.Message) {
 	bot.SendChat(m.Chat.ID, str)
 }
 
+func botDeregister(m *tb.Message) {
+	cc, ok := cfg.Clients[m.Sender.ID]
+	if !ok {
+		cc = &ClientConfig{
+			UserID:    m.Sender.ID,
+			Username:  m.Sender.Username,
+			CompanyID: 255,
+			TimeLeft:  0,
+		}
+		cfg.Clients[m.Sender.ID] = cc
+		bot.SendChat(m.Chat.ID, "User isn't registered.")
+		return
+	}
+	if cc.CompanyID != 255 {
+		for coID, co := range srv.Status.Companies {
+			if coID == cc.CompanyID {
+				cc.CompanyID = 255
+				bot.SendChat(m.Chat.ID, fmt.Sprintf("Deregistered from %s. %s playable left.", co.Name, cc.TimeLeft))
+				return
+			}
+		}
+		logInfoAlert("botRegister : %s : no such CompanyID : %d", cc.Username, cc.CompanyID)
+		cc.CompanyID = 255
+		bot.SendChat(m.Chat.ID, fmt.Sprintf("Registered company didn't exist anymore. %s playable left.", cc.TimeLeft))
+		return
+	}
+	return
+}
+
 func botRegister(m *tb.Message) {
 	cc, ok := cfg.Clients[m.Sender.ID]
 	if !ok {
@@ -177,9 +207,22 @@ func botRegister(m *tb.Message) {
 			UserID:    m.Sender.ID,
 			Username:  m.Sender.Username,
 			CompanyID: 255,
+			TimeLeft:  0,
 		}
 		cfg.Clients[m.Sender.ID] = cc
+	} else {
+		if cc.CompanyID != 255 {
+			for coID, co := range srv.Status.Companies {
+				if coID == cc.CompanyID {
+					bot.SendChat(m.Chat.ID, fmt.Sprintf("Already registered %s. Please /deregister first.", co.Name))
+					return
+				}
+			}
+			logInfoAlert("botRegister : %s : no such CompanyID : %d", cc.Username, cc.CompanyID)
+			cc.CompanyID = 255
+		}
 	}
+
 	coList := make(map[uint8]struct{})
 	for coID, _ := range srv.Status.Companies {
 		coList[coID] = struct{}{}
@@ -195,15 +238,44 @@ func botRegister(m *tb.Message) {
 
 		}
 	}
+
 	if len(coList) == 0 {
 		bot.SendChat(m.Chat.ID, "No company to register")
 		return
 	}
+
+	r := regexp.MustCompile("^\\/register( )+(?P<Company>[a-zA-Z\\.\\-0-9 ]+)$")
+	if r.MatchString(m.Text) {
+		// we have a parameter
+		coName := r.ReplaceAllString(m.Text, "${Company}")
+		for coID, co := range srv.Status.Companies {
+			if co.Name == coName {
+				for _, c := range cfg.Clients {
+					if c.CompanyID == coID {
+						bot.SendChat(m.Chat.ID, fmt.Sprintf("Company %s is already registered to @%s", coName, c.Username))
+						return
+					}
+				}
+				cc.CompanyID = coID
+				if cc.TimeLeft == 0 {
+					days := int(time.Now().Sub(cfg.Game.StartDate).Hours() / 24)
+					cc.TimeLeft = cfg.Game.StartingAllotment + cfg.Game.DailyAllotment*time.Duration(days)
+				}
+				bot.SendChat(m.Chat.ID, fmt.Sprintf("@%s registered %s (with %s playable)", cc.Username, srv.Status.Companies[cc.CompanyID].Name, cc.TimeLeft))
+				return
+			}
+		}
+		bot.SendChat(m.Chat.ID, fmt.Sprintf("Can't find company %s", coName))
+		return
+	}
+
 	if len(coList) == 1 {
 		for id, _ := range coList {
 			cc.CompanyID = id
-			days := int(time.Now().Sub(cfg.Game.StartDate).Hours() / 24)
-			cc.TimeLeft = cfg.Game.StartingAllotment + cfg.Game.DailyAllotment*time.Duration(days)
+			if cc.TimeLeft == 0 {
+				days := int(time.Now().Sub(cfg.Game.StartDate).Hours() / 24)
+				cc.TimeLeft = cfg.Game.StartingAllotment + cfg.Game.DailyAllotment*time.Duration(days)
+			}
 			bot.SendChat(m.Chat.ID, fmt.Sprintf("@%s registered %s (with %s playable)", cc.Username, srv.Status.Companies[cc.CompanyID].Name, cc.TimeLeft))
 			return
 		}
diff --git a/version.go b/version.go
index 8b8988c..9d8a435 100644
--- a/version.go
+++ b/version.go
@@ -1,6 +1,6 @@
 // Code generated by version.sh (@generated) DO NOT EDIT.
 package main
-var githash = "38a1d8a"
-var buildstamp = "2021-11-08_14:54:17"
-var commits = "174"
-var version = "38a1d8a-b174 - 2021-11-08_14:54:17"
+var githash = "93de432"
+var buildstamp = "2021-11-09_05:24:29"
+var commits = "175"
+var version = "93de432-b175 - 2021-11-09_05:24:29"